UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10‑K

 

Commission File No. 0‑14719

SKYWEST, INC.

 

444 South River Road

St. George, Utah 84790

(435) 634‑3000

Securities Registered Pursuant to Section 12(b) of the Act:

(Title of Each Class)                                                                                                                   (Name of Exchange on which Registered)

Common Stock, No Par Value                                                                                                          The Nasdaq Global Select Market

Securities Registered Pursuant to Section 12(g) of the Act: None

 

Indicate by check mark if the registrant is a well‑known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒  No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐  No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒  No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S‑T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒  No ☐

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S‑K (§ 229.405)is not contained herein, and will not be contained, to the best of registrant’s knowledge, in the definitive proxy or information statements incorporated by reference in Part III of this Form 10‑K or any amendment to this Form 10‑K. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non‑accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b‑2 of the Exchange Act.

 

 

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b‑2 of the Act). Yes ☐  No ☒

The aggregate market value of the registrant’s common stock held by non‑affiliates (based upon the closing sale price of the registrant’s common stock on The Nasdaq Global Select Market) on June 29, 2018 was approximately $2,701,175,567.

As of February 12,  2019, there were 51,635,965 shares of the registrant’s common stock outstanding.

Documents Incorporated by Reference

Portions of the registrant’s proxy statement to be used in connection with the registrant’s 2019 Annual Meeting of Shareholders are incorporated by reference into Part III of this Report as specified. Such proxy statement will be filed with the Securities and Exchange Commission not later than 120 days after the registrant’s fiscal year ended December 31, 2018.

 

 

 

SKYWEST, INC.

ANNUAL REPORT ON FORM 10‑K

TABLE OF CONTENTS

 

 

PART I

Unless otherwise indicated in this Report, “SkyWest,” “we,” “us,” “our” and similar terms refer to SkyWest, Inc., including SkyWest’s wholly-owned subsidiary SkyWest Airlines, Inc. “SkyWest Airlines” refers to our wholly‑owned subsidiary SkyWest Airlines, Inc., and "ExpressJet" refers to our former wholly-owned subsidiary ExpressJet Airlines, Inc.

On January 22, 2019, we completed the sale of ExpressJet.  Our financial and operating results for the years ended December 31, 2016, 2017 and 2018, and our financial position as of December 31, 2017 and 2018 contained in this Report, include the financial results and position of ExpressJet for those respective periods, as the sale of ExpressJet did not qualify for presentation of discontinued operations (see Note 2 in the accompanying financial statements). 

 

Cautionary Statement Concerning Forward‑Looking Statements

Certain of the statements contained in this Report should be considered “forward‑looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. These forward‑looking statements may be identified by words such as “may,” “will,” “expect,” “intend,” “anticipate,” “believe,” “estimate,” “plan,” “project,” “could,” “should,” “hope,” “likely,” and “continue” and similar terms used in connection with statements regarding our outlook, anticipated operations, the revenue environment, our contractual relationships, and our anticipated financial performance. These statements include, but are not limited to, statements about our future growth and development plans, including our future financial and operating results, our plans, objectives, expectations and intentions and other statements that are not historical facts. Readers should keep in mind that all forward‑looking statements are based on our existing beliefs about present and future events outside of our control and on assumptions that may prove to be incorrect. If one or more risks identified in this Report materializes, or any other underlying assumption proves incorrect, our actual results will vary, and may vary materially, from those anticipated, estimated, projected, or intended for a number of reasons, including but not limited to: the challenges of competing successfully in a highly competitive and rapidly changing industry; developments associated with fluctuations in the economy and the demand for air travel; the financial stability of United Airlines, Inc. (“United”), Delta Air Lines, Inc. (“Delta”), American Airlines, Inc. (“American”) and Alaska Airlines, Inc. (“Alaska”) (each, a “major airline partner”) and any potential impact of their financial condition on our operations; fluctuations in flight schedules, which are determined by the major airline partners for whom SkyWest conducts flight operations; variations in market and economic conditions; significant aircraft lease and debt commitments; realization of manufacturer residual value guarantees on applicable SkyWest aircraft; residual aircraft values and related impairment charges; the impact of global instability; labor relations and costs; potential fluctuations in fuel costs, and potential fuel shortages; the impact of weather-related or other natural disasters on air travel and airline costs; new aircraft deliveries; and the ability to attract and retain qualified pilots, as well as the other factors described below in Item 1A. Risk Factors.

There may be other factors that may affect matters discussed in forward‑looking statements set forth in this Report, which factors may also cause actual results to differ materially from those discussed. We assume no obligation to publicly update any forward‑looking statement to reflect actual results, changes in assumptions or changes in other factors affecting these statements other than as required by applicable law.

ITEM 1.  BUSINESS

General

We offer scheduled passenger service with approximately 2,770 daily departures to destinations in the United States, Canada, Mexico and the Caribbean. Substantially all of our flights are operated as Delta Connection, United Express, American Eagle or Alaska Airlines flights under code‑share arrangements (commercial agreements between airlines that, among other things, allow one airline to use another airline’s flight designator codes on its flights) with Delta, United, American or Alaska, respectively. We generally provide regional flying to our major airline partners under long‑term, fixed‑fee, code‑share agreements. Under these fixed‑fee agreements, our major airline partners generally pay us fixed rates for operating the aircraft primarily based on the number of completed flights, flight time and the number of aircraft under contract. The major airline partners also reimburse us for specified direct operating expenses (including fuel expense).

SkyWest has been flying since 1972. During our long operating history, we have developed an industry‑leading reputation for providing quality regional airline service. As of December 31, 2018, we had 596 aircraft in scheduled service consisting of the following (which included 100 Embraer ERJ145 regional jet (“ERJ145”) aircraft and 16 Bombardier CRJ200 regional jet (“CRJ200”) aircraft that ExpressJet operated for United, and 10 Canadair CRJ700 regional jet (“CRJ700”) aircraft that ExpressJet operated for American):

*As of December 31, 2018, these aircraft have been removed from service and are in the process of being returned under the applicable leasing arrangement or are aircraft transitioning between code-share agreements with our major airline partners.

 

As of December 31, 2018, our fleet scheduled for service consisted of aircraft manufactured by Bombardier Aerospace (“Bombardier”) and Embraer S.A. (“Embraer”) summarized as follows:

 

Bombardier and Embraer are the primary manufacturers of regional jets operated in the United States and offer many of the amenities of larger commercial jet aircraft, including flight attendant service, a stand‑up cabin, overhead and under seat storage, lavatories and in‑flight snack and beverage service. The speed of Bombardier and Embraer regional jets is comparable to larger aircraft operated by major airlines, and they have a range of approximately 1,600 miles and 2,100 miles, respectively.

We were incorporated in Utah in 1972. Our principal executive offices are located at 444 South River Road, St. George, Utah 84790, and our primary telephone number is (435) 634‑3000. We maintain an internet website at inc.skywest.com, which provides links to our annual, quarterly and current reports filed with the Securities and Exchange Commission (“SEC”). The information on our website does not constitute part of this Report. In addition, we provide electronic or paper copies of our SEC filings free of charge upon request.

Our Operating Platforms

SkyWest

We provide regional jet service to airports throughout the United States, as well as Mexico and Canada. As of December 31, 2018, we offered approximately 2,170 daily departures, of which approximately 820 were United Express flights, 920 were Delta Connection flights, 290 were American Eagle flights and 140 were Alaska Airlines flights. Our operations are conducted principally from airports located in Chicago (O’Hare), Denver, Houston, Los Angeles,

Minneapolis, Phoenix, Salt Lake City, San Francisco and Seattle. As of December 31, 2018, we operated a fleet of 470 aircraft consisting of the following:

We conduct our code‑share operations with our major airline partners pursuant to the following agreements:

A summary of the terms for each of our code‑share agreements is provided under the heading “Code-Share Agreements” below on page 6.

ExpressJet

Prior to our sale of ExpressJet in January 2019, ExpressJet provided regional jet service to airports primarily located in the Eastern and Midwestern United States, as well as Mexico, Canada and the Caribbean.  ExpressJet’s operations were conducted principally from airports located in Atlanta, Chicago (O’Hare), Houston, Newark and New York. During the year ended December 31, 2018, ExpressJet offered approximately 600 daily departures, of which approximately 90 were Delta Connection flights, 440 were United Express flights and 70 were American Eagle flights. As of December 31, 2018, ExpressJet operated a fleet of 126 aircraft consisting of the following:

SkyWest Leasing

The SkyWest Leasing segment includes revenue attributed to our Embraer E175 dual-class regional jet aircraft (“E175”) ownership cost earned under the applicable fixed-fee contracts, and the depreciation and interest expense of our E175 aircraft.  The SkyWest Leasing segment’s total assets and capital expenditures include the acquired E175 aircraft.  The SkyWest Leasing segment additionally includes the income from CRJ200 aircraft leased to a third-party.

Competition and Economic Conditions

The airline industry is highly competitive. SkyWest competes principally with other regional airlines. Our operations extend throughout most major geographic markets in the United States. Our competition includes, therefore, nearly every other domestic regional airline. Our primary competitors include Air Wisconsin Airlines Corporation (“Air Wisconsin”); Endeavor Air, Inc. (“Endeavor”) (owned by Delta); Envoy Air Inc. (“Envoy”), PSA Airlines, Inc. (“PSA”) and Piedmont Airlines (“Piedmont”) (Envoy, PSA and Piedmont are owned by American); ExpressJet Airlines (subsequent to January 2019); Horizon Air Industries, Inc. (“Horizon”) (owned by Alaska Air Group, Inc.); Mesa Air Group, Inc. (“Mesa”); Republic Airways Holdings Inc. (“Republic”); and Trans States Airlines, Inc. (“Trans States”). Major airlines typically award code-share flying arrangements to regional airlines based primarily upon the following criteria: ability to fly contracted schedules, availability of labor resources, including pilots, low operating cost, financial

resources, geographical infrastructure, overall customer service levels relating to on‑time arrival and flight completion percentages and the overall image of the regional airline.

The principal competitive factors for regional airline code‑share arrangements include labor resources, code‑share agreement terms, reliable flight operations, operating cost structure, ability to finance new aircraft, certification to operate certain aircraft types and geographical infrastructure and markets and routes served.

Our operations represent the largest regional airline operations in the United States. However, regional carriers owned by major airlines may have access to greater resources than we do through their parent companies.

Generally, the airline industry is sensitive to changes in general economic conditions. Economic downturns, combined with competitive pressures, have contributed to a number of reorganizations, bankruptcies, liquidations and business combinations among major and regional carriers. The effect of economic downturns may be somewhat mitigated by our predominantly contract-based flying arrangements. If, however, any of our major airline partners experience a prolonged decline in the number of passengers or are negatively affected by low ticket prices or high fuel prices, they may seek rate reductions in future code-share agreements, or materially reduce scheduled flights in order to reduce their costs. In addition, adverse weather conditions can impact our ability to complete scheduled flights and can have a negative impact on our operations and financial condition.  

Industry Overview

Majors, Low-Cost Carriers and Regional Airlines

The airline industry in the United States has traditionally been comprised of several major airlines, including Alaska, American, Delta and United. The major airlines offer scheduled flights to most major U.S. cities, numerous smaller U.S. cities, and cities throughout the world through a hub and spoke network.

Low-cost carriers, such as Southwest Airlines Co. (“Southwest”) and JetBlue Airways Corporation (“JetBlue”), generally offer fewer conveniences to travelers and have lower cost structures than major airlines, which permits them to offer flights to and from many of the same markets as the major airlines, but at lower prices.

Regional airlines, including SkyWest, typically operate smaller aircraft on shorter distance routes than major and low‑cost carriers. Several regional airlines, including Endeavor, Envoy, Horizon, Piedmont and PSA, are wholly‑owned subsidiaries of major airlines.

Regional airlines generally do not try to establish an independent route system to compete with the major airlines. Rather, regional airlines typically enter into relationships with one or more major airlines, pursuant to which the regional airline agrees to use its smaller, lower‑cost aircraft to carry passengers booked and ticketed by the major airline between a hub of the major airline and a smaller outlying city. In exchange for such services, the major airline pays the regional airline either a fixed flight fee, termed “contract” or “fixed‑fee” flights, or the regional airline receives a percentage of applicable passenger ticket revenues, termed “prorate” or “revenue‑sharing” flights, as described in more detail below.

Code‑Share Agreements

Regional airlines generally enter into code‑share agreements with major airlines, pursuant to which the regional airline is authorized to use the major airline’s two‑letter flight designator codes to identify the regional airline’s flights and fares in the central reservation systems, to paint its aircraft with the colors and/or logos of the major airline and to market and advertise its status as a carrier for the major airline. Code‑share agreements also generally obligate the major airline to provide services such as reservations, ticketing, ground support and gate access to the regional airline, and the major airline often coordinates marketing, advertising and other promotional efforts. In exchange, the regional airline provides a designated number of low‑capacity (usually between 50 and 76 seats) flights between larger airports served by the major airline and surrounding cities, usually in lower‑volume markets. The financial arrangements between the regional airlines and their code‑share partners usually involve either fixed‑fee arrangements or revenue‑sharing arrangements as explained below:

We have code‑share agreements with United, Delta, American and Alaska. ExpressJet had code‑share agreements with United, Delta and American during 2018.

During the year ended December 31, 2018, approximately 84.3% of our and ExpressJet’s flying agreements revenue related to fixed‑fee contract flights, where Delta, United, American and Alaska controlled scheduling, ticketing, pricing and seat inventories. The remainder of our flying agreements revenue during the year ended December 31, 2018 related to prorate flights for Delta, United or American, where we controlled scheduling, pricing and seat inventories, and shared passenger fares with Delta, United or American according to prorate formulas.

Under our fixed-fee arrangements, our major airline partners compensate us for our costs of owning or leasing the aircraft on a monthly basis. The aircraft compensation structure varies by agreement, but is intended to cover either our aircraft principal and interest debt service costs, our aircraft depreciation and interest expense or our aircraft lease expense costs while the aircraft is under contract. The number of aircraft under our fixed‑fee arrangements and our prorate arrangements as of December 31, 2018 is reflected in the summary below. The following summaries of our code-share agreements with our major airline partners do not purport to be complete and are qualified in their entirety by reference to the applicable agreement.

Delta Connection Agreements

 

United Express Agreements

 

American Agreements

 

Alaska Capacity Purchase Agreement

 

As of December 31, 2018, ExpressJet operated 100 ERJ145 aircraft and 16 CRJ200 aircraft under fixed-fee agreements with United and 10 CRJ700 aircraft under a fixed-fee agreement with American.  We sold ExpressJet in January 2019.  In conjunction with the sale of ExpressJet, SkyWest retained ownership of the 16 CRJ200 aircraft and the 10 CRJ700 aircraft operated by ExpressJet as of December 31, 2018. We agreed to lease the 16 CRJ200 aircraft to ExpressJet for up to a five-year period.  We are pursuing alternative uses of the 10 CRJ700 aircraft, including but not limited to, using the aircraft under fixed-fee agreements or leasing the aircraft or related engines to third parties.  ExpressJet leased 100 ERJ145 from United and the ERJ145 aircraft remained with ExpressJet in conjunction with the sale of ExpressJet.

In addition to the contractual arrangements described above, we have entered into agreements with Alaska and Delta to acquire and operate additional E175 dual-class regional jet aircraft (which are typically configured with 76 or 70 seats)  for those major airline partners.  As of December 31, 2018, we anticipated placing an additional three E175 aircraft with Alaska and nine E175 aircraft with Delta. The delivery dates for the new E175 aircraft are expected to take place from 2019 through 2021. Final delivery dates may be adjusted based on various factors.

We also entered into an agreement with Delta to operate 20 new Canadair CRJ900 regional jet aircraft (“CRJ900”). The aircraft will be acquired by Delta and operated by us under a fixed-fee agreement.  As of December 31, 2018, we had taken delivery of five of these CRJ900 aircraft and placed them into service, and anticipate the delivery of the remaining 15 aircraft will continue through the end of 2020. These aircraft will replace 20 CRJ700 aircraft scheduled to expire under our flying contracts with Delta.

Delta Connection Agreements

We and Delta are parties to a Delta Connection Agreement (the "Delta Connection Agreement"), pursuant to which we provide contract flight services for Delta.

The Delta Connection Agreement has a latest scheduled termination date of 2029. The Delta Connection Agreement is subject to early termination in various circumstances, including:

United Express Agreements

We and United are parties to two United Express agreements: a United Express agreement to operate certain CRJ200s and CRJ700s, and a United Express agreement to operate E175 aircraft (collectively, the “United Express Agreements”).

The United Express Agreements have a latest scheduled termination date in 2027. The United Express Agreements are subject to early termination in various circumstances including:

American Agreement

We and American are parties to an agreement (the “American Agreement”) for the operation of CRJ700 aircraft. The American Agreement for CRJ700 aircraft is scheduled to terminate in 2023 and is subject to early termination in various circumstances including:

Alaska Agreement

We and Alaska are parties to a Capacity Purchase Agreement (the “Alaska Agreement”) for the operation of E175 aircraft. The agreement has a 12‑year term for each of the aircraft subject to the agreement. The Alaska Agreement is subject to early termination in various circumstances including:

Training and Aircraft Maintenance

SkyWest provides substantially all training to our crew members and maintenance personnel at our training facilities. Our employees perform routine airframe and engine maintenance along with periodic inspections of equipment at our maintenance facilities. We also use third‑party vendors for certain airframe and engine maintenance work.

Fuel

Our fixed‑fee agreements with Delta, United, American and Alaska require the respective major airline partner to reimburse us for the fuel costs we incur under those agreements, thereby reducing our exposure to fuel price fluctuations. Under our prorate agreements with Delta, United and American, we are responsible for the costs to operate the flights, including fuel costs, and therefore we are exposed to fuel price fluctuations for flights operated under our prorate agreements. During the year ended December 31, 2018, United and Delta purchased the majority of the fuel for our aircraft flying under their respective fixed-fee agreements directly from their fuel vendors. Historically, we have not experienced problems with the availability of fuel, and believe we will be able to obtain fuel in quantities sufficient to meet our existing and anticipated future requirements at competitive prices. Standard industry fuel purchase contracts generally do not provide protection against fuel price increases, nor do they ensure availability of supply. We typically purchase fuel from third-party suppliers for our prorate agreements. A substantial increase in the price of jet fuel for flights we operate under our prorate agreements, or the lack of adequate fuel supplies in the future, could have a material adverse effect on our business, financial condition, results of operations or liquidity.

Employee Matters

Collective Bargaining

As of December 31, 2018, we had approximately 15,900 full‑time equivalent employees, including 2,932 employed by ExpressJet. Approximately 85.3% of these employees were represented by a labor group. As of December 31, 2018, approximately 2,320 of ExpressJet’s 2,932 employees were represented by a national union.

As of December 31, 2018, SkyWest and SkyWest Airlines collectively employed 12,968 full‑time equivalent employees, consisting of 4,706 pilots, 3,843 flight attendants, 1,633 customer service personnel, 1,208 mechanics, 893 other maintenance personnel, 190 dispatchers and 495 operational support and administrative personnel. None of these employees are currently represented by a national union. Our employees are represented by in-house labor associations

that have entered into collective bargaining agreements regarding our employee compensation and work rules.  Union organizing efforts among our employees do occur from time to time and may continue in the future. If unionization efforts are successful, we may be subjected to increased risks of work interruption or stoppage and/or incur additional expenses associated with increased union representation of our employees. Neither SkyWest nor SkyWest Airlines has ever experienced a work stoppage due to a strike or other labor dispute, and we consider our relationships with our employees to be good.

Our relations with labor unions in the United States are governed by the Railway Labor Act (the “RLA”). Under the RLA, a collective bargaining agreement between an airline and a labor representative does not expire, but instead becomes amendable as of a stated date. If either party wishes to modify the terms of any such agreement, it must notify the other party in the manner prescribed by the RLA and/or described in the agreement. After receipt of such notice, the parties must meet for direct negotiations, and if no agreement is reached, either party may request the National Mediation Board to initiate a process including mediation, arbitration, and a potential “cooling off” period that must be followed before either party may engage in “self-help.” “Self-help” includes, among other things, a strike by the representative or the imposition of proposed changes to the collective bargaining agreement by the airline. The U.S. Congress and the President have the authority to prevent “self-help” by enacting legislation that, among other things, imposes a settlement on the parties.

Government Regulation

All interstate air carriers, including SkyWest, are subject to regulation by the U.S. Department of Transportation (the “DOT”), the U.S. Federal Aviation Administration (the “FAA”) and other governmental agencies. Regulations promulgated by the DOT primarily relate to economic aspects of air service. The FAA requires operating, air worthiness and other certificates; approval of personnel who may engage in flight, maintenance or operating activities; record‑keeping procedures in accordance with FAA requirements; and FAA approval of flight training and retraining programs. Generally, governmental agencies enforce their regulations through, among other methods, certifications, which are necessary for the continued operations of SkyWest, and proceedings, which can result in civil or criminal penalties or revocation of operating authority. The FAA can also issue maintenance directives and other mandatory orders relating to, among other things, grounding of aircraft, inspection of aircraft, installation of new safety‑related items and the mandatory removal and replacement of aircraft parts.

We believe SkyWest is in compliance in all material respects with FAA regulations and holds all operating and airworthiness certificates and licenses which are necessary to conduct our operations. We incur substantial costs in maintaining current certifications and otherwise complying with the laws, rules and regulations to which we are subject. Our flight operations, maintenance programs, record keeping and training programs are conducted under FAA approved procedures. All air carriers operating in the United States are required to comply with federal laws and regulations pertaining to noise abatement and engine emissions. All such air carriers are also subject to certain provisions of the Federal Communications Act of 1934, as amended, because of their extensive use of radio and other communication facilities. SkyWest is also subject to certain federal and state laws relating to protection of the environment, labor relations and equal employment opportunity. We believe SkyWest is in compliance in all material respects with these laws and regulations.

Environmental Matters

We are subject to various federal, state, local and foreign laws and regulations relating to environmental protection matters. These laws and regulations govern such matters as environmental reporting, storage and disposal of materials and chemicals and aircraft noise. We are, and expect in the future to be, involved in various environmental matters and conditions at, or related to, our properties. We are not currently subject to any environmental cleanup orders or actions imposed by regulatory authorities. We are not aware of any active material environmental investigations related to our assets or properties.

Safety and Security

We are committed to the safety and security of our passengers and employees. We have taken many steps, both voluntarily and as mandated by governmental authorities, to increase the safety and security of our operations. Some of the safety and security measures we have taken with our major airline partners include: aircraft security and surveillance, positive bag matching procedures, enhanced passenger and baggage screening and search procedures, and securing of cockpit doors. We are committed to complying with future safety and security requirements.

Insurance

We maintain insurance policies we believe are of types customary in the industry and in amounts we believe are adequate to protect against material loss. These policies principally provide coverage for public liability, passenger liability, baggage and cargo liability, property damage, including coverage for loss or damage to our flight equipment, and workers’ compensation insurance.

Seasonality

Our results of operations for any interim period are not necessarily indicative of those for the entire year, in part because the airline industry is subject to seasonal fluctuations and changes in general economic conditions. Our operations are somewhat favorably affected by pleasure travel on our prorate routes, historically contributing to increased travel in the summer months, and are unfavorably affected by decreased business travel during the months from November through January and by inclement weather which can result in cancelled flights, principally during the winter months. Additionally, a significant portion of our fixed‑fee arrangements is based on completing flights and we typically have more scheduled flights during the summer months. We generally experience a significantly higher number of weather cancellations during the winter months, which negatively impacts our revenue during such months.

ITEM 1A.  RISK FACTORS

In addition to factors discussed elsewhere in this Report, the following are important risks which could adversely affect our future results. Additional risks and uncertainties not presently known to us or that we currently do not deem material may also impair our business operations. If any of the risks we describe below occur, or if any unforeseen risk develops, our operating results may suffer, our financial condition may deteriorate, the trading price of our common stock may decline and investors could lose all or part of their investment in us.

Risks Related to Our Operations

Our business model is dependent on code-share agreements with four major airline partners.

Our business model depends on major airlines electing to contract with us instead of operating their own regional jets. Some regional airlines are owned by a major airline. We have no guarantee that in the future our major airline partners will choose to enter into contracts with us instead of operating their own regional jets. Our major airline partners are not prohibited from doing so under our code‑share agreements. A decision by any of our major airline partners to phase out code‑share relationships and instead acquire and operate their own regional jets could have a material adverse effect on our financial results.

As of December 31, 2018, 489 out of our total 596 aircraft available for scheduled service were operating under a fixed‑fee arrangement or a revenue‑sharing agreement with either Delta or United. If our code‑share relationship with Delta or United were terminated, we would be significantly impacted and likely would not have an immediate source of revenue or earnings to offset such loss. A termination of either of these relationships would likely have a material adverse effect on our financial condition, operating revenues and net income unless we are able to enter into satisfactory substitute arrangements for the utilization of the affected aircraft by other code‑share partners, or, alternatively, obtain the airport facilities and gates and make the other arrangements necessary to fly as an independent airline. We may not be able to enter into substitute code‑share arrangements, and any such arrangements we might secure may not be as favorable to us as our current agreements. Operating an airline independent from major airline partners would be a

significant departure from our business plan and would likely require significant time and resources, which may not be a viable alternative.

Additionally, each of our agreements with our major airline partners is subject to certain early termination provisions. For example, Delta’s termination rights include the right to terminate the agreements upon the occurrence of certain force majeure events (including certain labor‑related events) that prevent us from performing for certain periods and the right to terminate the agreements if we fail to maintain competitive base rate costs, subject to certain rights to take corrective action to reimburse Delta for lost revenues. United may terminate the United Express Agreements due to our uncured breach of certain operational or performance provisions, including measures and standards related to flight completions, baggage handling and on‑time arrivals. We currently use the systems, facilities and services of Delta and United to support a significant portion of our operations, including airport and terminal facilities and operations, information technology support, ticketing and reservations, scheduling, dispatching, fuel purchasing and ground handling services. If Delta or United were to cease to maintain any of these systems, close any of these facilities or no longer provide these services to us, due to termination of one of our code‑share agreements, a strike or other labor interruption by Delta or United personnel or for any other reason, we may not be able to obtain alternative systems, facilities or services on terms and conditions as favorable as those we currently receive, or at all. Since our revenues and operating profits are dependent on our level of flight operations, we could then be forced to significantly reduce our operations. Furthermore, upon certain terminations of our code‑share agreements, Delta and United could require us to sell or assign to them facilities and assets, including maintenance facilities, we use in connection with the code‑share services we provide. As a result, in order to offer airline service after termination of any of our code‑share agreements, we may have to replace these facilities, assets and services. We may be unable to arrange such replacements on satisfactory terms, or at all.

We are reliant on two aircraft manufacturers and one engine manufacturer.

We operate aircraft manufactured by Bombardier and Embraer.  The issuance of FAA or manufacturer directives restricting or prohibiting the use of any Bombardier or Embraer aircraft types we operate could negatively impact our business and financial results.  We are also dependent upon General Electric as the sole manufacturer of engines used on the aircraft we operate.  Our operations could be materially and adversely affected by the failure or inability of Bombardier, Embraer or General Electric to provide sufficient parts or related maintenance and support services to us on a timely manner. Additionally, timing of aircraft deliveries could be delayed.

Our growth may be limited with our major airline partners' flight systems.

Additional growth opportunities within our major airline partners’ flight systems are limited by various factors, including a limited number of regional aircraft each such major airline partner can operate in its regional network due to its own labor agreements. Except as contemplated by our existing code‑share agreements, we cannot be sure that our major airline partners will contract with us to fly any additional aircraft. We may not receive additional growth opportunities, or may agree to modifications to our code‑share agreements that reduce certain benefits to us in order to obtain additional aircraft, or for other reasons. Given the competitive nature of the airline industry, we believe limited growth opportunities may result in competitors accepting reduced margins and less favorable contract terms in order to secure new or additional code‑share operations. Even if we are offered growth opportunities by our major airline partners, those opportunities may involve economic terms or financing commitments that are unacceptable to us. Additionally, our major airline partners may reduce the number of regional jets in their system by not renewing or extending existing flying arrangements with regional operators. Any one or more of these factors may reduce or eliminate our ability to expand our flight operations with our existing major airline partners.

Increases in labor costs, including pilot costs, maintenance costs and overhead costs may result in lower operating margins under our fixed-fee contracts.

Labor costs are a significant component of our total expenses. Currently, we believe our labor costs are competitive relative to other regional airlines. However, we cannot provide assurance that our labor costs going forward will remain competitive because of changes in supply and demand for labor in the regional industry. We compete against other airlines and businesses for labor in many highly skilled positions. If we are unable to hire, train and retain qualified employees at a reasonable cost, sustain employee engagement in our strategic vision, or if we are unsuccessful at implementing succession plans for our key staff, we may be unable to grow or sustain our business. Attrition beyond

normal levels could negatively impact our operating results, increase our training and labor costs and our business prospects could be harmed.

 

Additionally, under our fixed-fee contracts with Delta, United, American and Alaska, a portion of our compensation is based upon pre‑determined rates typically applied to production statistics (such as departures, block hours, flight hours and number of aircraft in service each month). The primary operating costs intended to be compensated by the pre-determined rates include labor costs, including crew training costs, certain aircraft maintenance expenses, and overhead costs.  During the year ended December 31, 2018, approximately 90.1% of our code‑share operating costs were reimbursable at pre‑determined rates and 9.9% of our code‑share operating costs were pass‑through costs.  Additionally, our aircraft maintenance costs may increase annually as our fleet ages at a higher rate than our pre-determined rates allow.  If our operating costs for labor, aircraft maintenance and overhead costs exceed the compensation earned from our pre‑determined rates under our fixed‑fee arrangements, our financial position and operating results will be negatively affected.

Information technology security breaches, hardware or software failures, or other information technology disruptions may negatively impact our operations or reputation.

The performance and reliability of our technology are critical to our ability to compete effectively. Any internal technological error or failure or large‑scale external interruption in the technological infrastructure we depend on, such as power, telecommunications or the internet, may disrupt our internal network. Any individual, sustained or repeated failure of technology could impact our ability to conduct our business and result in increased costs. Our technological systems and related data may be vulnerable to a variety of sources of interruption due to events beyond our control, including natural disasters, terrorist attacks, telecommunications failures, computer viruses, hackers and other security issues.

In addition, as a part of our ordinary business operations, we collect and store sensitive data, including personal information of our passengers and employees and information of our business partners. Our information systems are subject to an increasing threat of continually evolving cybersecurity risks. Unauthorized parties may attempt to gain access to our systems or information through fraud or other means of deception. The methods used to obtain unauthorized access, disable or degrade service or sabotage systems are constantly evolving, and may be difficult to anticipate or to detect for long periods of time. We may not be able to prevent all data security breaches or misuse of data. The compromise of our technology systems resulting in the loss, disclosure, misappropriation of, or access to, customers’, employees’ or business partners’ information could result in legal claims or proceedings, liability or regulatory penalties under laws protecting the privacy of personal information, disruption to our operations and damage to our reputation, any or all of which could adversely affect our business and financial condition.

We may experience disruption in service with key third-party service providers.

We rely on outside vendors for a variety of services and functions critical to our business, including airframe and engine maintenance, ground handling, fueling, computer reservation system hosting, telecommunication systems and information technology infrastructure and services.

 

Even though we strive to formalize agreements with these vendors that define expected service levels, our use of outside vendors increases our exposure to several risks. In the event that one or more vendors goes into bankruptcy, ceases operation or fails to perform as promised, replacement services may not be readily available at competitive rates, or at all. If one of our vendors fails to perform adequately, we may experience increased costs, delays, maintenance issues, safety issues or negative public perception of our airline. Vendor bankruptcies, unionization, regulatory compliance issues or significant changes in the competitive marketplace among suppliers could adversely affect vendor services or force us to renegotiate existing agreements on less favorable terms. These events could result in disruptions in our operations or increases in our cost structure.

 

The Airline Safety and Pilot Training Improvement Act of 2009 may continue to negatively affect our operations and financial condition.

The Airline Safety and Pilot Training Improvement Act of 2009 (the “Improvement Act”) became effective in August 2013. The Improvement Act added new certification requirements for entry‑level commercial pilots, requires additional emergency training for airline personnel, improves availability of pilot records and mandates stricter rules to minimize pilot fatigue.

 

The Improvement Act also:

 

 The Improvement Act (and associated regulations) has increased our compliance and FAA reporting obligations, has had a negative effect on pilot scheduling, work hours and the number of pilots required to be employed for our operations or other aspects of our operations, and may continue to negatively impact our operations and financial condition.

 

We have aircraft lease and debt commitments that extend beyond our existing fixed‑fee contractual term on certain aircraft.

Under our fixed‑fee arrangements with multiple major airline partners we have a total of 53 CRJ700s/CRJ900s with flying contract expirations in 2019 and 2020. Our underlying lease or debt financing obligations associated with each of these aircraft are scheduled to terminate in 2024 and 2025 on an aircraft‑by‑aircraft basis. We may not be successful in extending the flying contract term on these aircraft with our major airline partner at acceptable economic terms. In the event we are unsuccessful in extending the flying contract terms on these aircraft, we intend to pursue alternative uses for the aircraft over the remaining aircraft financing term including, but not limited to, operating the aircraft with another major carrier under a negotiated code‑share agreement or subleasing the aircraft to another operator. Additionally, we may negotiate an early lease return agreement with the aircraft lessor.  In the event we are unable to extend the flying contract terms for these aircraft at each respective contract’s expiration, we may incur cash and non-cash early lease termination costs that would negatively impact our operations and financial condition.  Additionally, in the event we are unable to extend a flying contract with an existing major airline partner, but reach an agreement to place the aircraft into service with a different major airline partner, we likely will incur inefficiencies and incremental costs, such as changing the aircraft livery, which would negatively impact our financial results.

Our sale of ExpressJet may negatively impact our financial results, and we may not be successful in growing our business, revenues and profits from operations independent of ExpressJet.

Prior to the sale of ExpressJet in January 2019, 17.5% of our total revenue for the year ended December 31, 2018 was generated by regional jet service provided by ExpressJet.  Following the sale of ExpressJet, we expect that our revenues will be materially reduced as we are no longer generating revenue from the operations of ExpressJet.  We also expect the sale of ExpressJet to reduce the overall scale and resources of our business, which could adversely impact our ability to compete against other regional and low-cost carriers, particularly those owned by major airlines that may have

access to greater resources through their parent companies.  There can be no assurance that the proceeds and other benefits from the sale of ExpressJet will be sufficient for us to grow our business, revenues and profits, and our future growth will depend on our ability to successfully implement our business strategy independent of ExpressJet going forward. If we are unable to successfully execute on this business strategy, or otherwise compete effectively with other regional and low-cost airlines, our business, financial condition, results of operations and growth prospects could be materially and adversely affected.

There are long‑term risks related to supply and demand of regional aircraft associated with our regional airline services strategy.

Our major airline partners have indicated that their committed supply of regional airline capacity is larger than they desire given current market conditions. Specifically, they have identified a general oversupply of 50‑seat regional jets under contractual commitments with regional airlines. Delta in particular has reduced both the number of 50‑seat regional jets within its network and the number of regional airlines with which it contracts. In addition to reducing the number of 50‑seat jets under contract, major airlines have reduced the utilization of regional aircraft, thereby reducing the revenue paid to regional airlines under capacity purchase agreements. This decrease has had, and may continue to have, a negative impact on our regional airline services revenue and financial results.

The residual value of our owned aircraft may be less than estimated in our depreciation policies.

 

As of December 31, 2018, we had approximately $5.0 billion of property and equipment and related assets, net of accumulated depreciation.  In accounting for these long‑lived assets, we make estimates about the expected useful lives of the assets, the expected residual values of certain of these assets, and the potential for impairment based on the fair value of the assets and the cash flows they generate.  Factors indicating potential impairment include, but are not limited to, significant decreases in the market value of the long‑lived assets, a significant change in the condition of the long‑lived assets and operating cash flow losses associated with the use of the long‑lived assets.  In the event the estimated residual value of any of our aircraft types is determined to be lower than the residual value assumptions used in our depreciation policies, the applicable aircraft type in our fleet may be impaired and may result in a material reduction in the book value of applicable aircraft types we operate or we may need to prospectively modify our depreciation policies. For example, during 2016 we recorded an impairment of $465.6 million attributable to certain long-lived assets associated with our 50-seat aircraft primarily resulting from changes to our short-term and long-term fleet plans with our 50-seat aircraft. An impairment on any of our aircraft types we operate or an increased level of depreciation expense resulting from a change to our depreciation policies could result in a material negative impact to our financial results.

Interruptions or disruptions in service at one of our hub airports, due to weather, system malfunctions or for any other reason, could have a material adverse impact on our operations.

We currently operate primarily through hubs across the United States. Nearly all of our flights either originate from or fly into one of these hubs. Our revenues depend primarily on our completion of flights and secondarily on service factors such as timeliness of departure and arrival. Any interruptions or disruptions could, therefore, severely and adversely affect us. Extreme weather such as hurricanes or tornados can cause flight disruptions, and, during periods of storms or adverse weather, our flights may be canceled or significantly delayed. We operate a significant number of flights to and from airports with particular weather difficulties, including Atlanta, Salt Lake City, Chicago, San Francisco and Denver. A significant interruption or disruption in service at one of our hubs, due to adverse weather, system malfunctions, security closures or otherwise, could result in the cancellation or delay of a significant portion of our flights and, as a result, could have a severe adverse impact on our operations and financial performance.

Negative economic or industry conditions may result in reductions to our flight schedules, which could materially and adversely affect our operations and financial condition.

Our operations and financial condition are affected by many changing economic and other conditions beyond our control, including, among others:

The effect of any, or some combination, of the foregoing economic and industry conditions on our operations or financial condition is virtually impossible to forecast; however, the occurrence of any or all of such conditions in a significant manner could materially and adversely affect our operations and financial condition and could cause our major airline partners to reduce the utilization levels of our aircraft under our code-share agreements.

The majority of our code‑share agreements set forth minimum levels of flight operations which our major airline partners are required to schedule for our operations and we are required to provide. These minimum flight operating levels are intended to provide a baseline level of expected utilization of aircraft, labor, maintenance facilities and related flight operations support. Historically, our major airline partners have utilized our flight operations at levels which exceed the minimum levels set forth in our code‑share agreements, however, the occurrence of any or all of the foregoing economic and industry conditions may cause our major airline partners to reduce our utilization levels. If our major airline partners schedule the utilization of our aircraft below historical levels (including taking into account the route distances and frequency of our scheduled flights), we may not be able to maintain operating efficiencies previously obtained, which would negatively impact our operating results and financial condition. Additionally, our major airline partners may change routes and frequencies of flights, which can negatively impact our operating efficiencies. Changes in schedules may increase our flight costs, which could exceed the reimbursed rates paid by our major airline partners. Continued reduced utilization levels of our aircraft or other changes to our schedules under our code‑share agreements would adversely impact our financial results.

We may experience an increase in fuel prices in our prorate operations.

Dependence on foreign imports of crude oil, limited refining capacity and the possibility of changes in government policy on jet fuel production, transportation and marketing make it impossible to predict the future availability of jet fuel. If there are additional outbreaks of hostilities or other conflicts in oil‑producing areas or elsewhere, or a reduction in refining capacity (due to weather events, for example), or governmental limits on the production or sale of jet fuel, there could be a reduction in the supply of jet fuel and significant increases in the cost of jet fuel. Additionally, our operations may experience disruptions from temporary fuel shortages by our fuel vendors resulting from fuel quality issues, refueling disruption, or other challenges.   Major reductions in the availability of jet fuel or significant increases in its cost, or a continuation of high fuel prices for a significant period of time, would have a material adverse impact on us.

Pursuant to our fixed‑fee arrangements, our major airline partners have agreed to bear the economic risk of fuel price fluctuations on our contracted flights. However, we bear the economic risk of fuel price fluctuations on our prorate operations. As of December 31, 2018, we operated 25 CRJ200s under a prorate agreement with United, 29 CRJ200s under a prorate agreement with Delta, and seven CRJ200s under a prorate agreement with American. Our operating and financial results with respect to these prorate arrangements can be negatively affected by the price of jet fuel in the event we are unable to increase our passenger fares. Additionally in the event of prolonged low fuel prices, our competitors may lower their passenger ticket prices on routes that compete with our prorate markets, which could negatively impact our passenger load factors.

Our prorate arrangements with our major airline partners are terminable upon notice of 120 days or less.

Our prorate flying agreements with our major airline partners permit the major airline partner to terminate the agreement in its discretion by giving us notice of 120 days or less.  If one of our major airline partners elects to terminate a flying agreement with notice of 120 days or less, our ability to use the aircraft under an alternative agreement with similar economics may be limited, which could negatively impact our financial results.  Additionally, even if we can subsequently place the aircraft into service with a different major airline partner, of which there can be no assurance, we likely would incur inefficiencies and incremental costs, such as changing the aircraft livery, during the transition period, which would negatively impact our financial results.

We have a significant amount of contractual obligations.

As of December 31, 2018, we had a total of approximately $3.2 billion in total long‑term debt obligations. Substantially all of this long‑term debt was incurred in connection with the acquisition of aircraft and engines. We also have significant long‑term lease obligations primarily relating to our aircraft fleet. These leases are classified as operating leases and therefore are not reflected as liabilities in our consolidated balance sheets. At December 31, 2018, we had 260 aircraft under lease, with remaining terms ranging up to nine years. Future minimum lease payments due under all long‑term operating leases were approximately $477.9 million at December 31, 2018. At a 5.45% discount factor, which is the average rate used to approximate the implicit rates within the applicable aircraft leases, the present value of these lease obligations was equal to approximately $399.2 million at December 31, 2018. Our high level of fixed obligations could impact our ability to obtain additional financing to support additional expansion plans or divert cash flows from operations and expansion plans to service the fixed obligations.

Our anticipated fleet replacement would require a significant increase in our leverage and the related cash requirements.

We currently have 200 CRJ200s with an average life of 16.3 years. Over the next several years, we may continue to replace the CRJ200s with larger regional jets. If we continue to add new aircraft to our fleet, we anticipate using significant amounts of capital to acquire these larger regional jets.

There can be no assurance that our operations will generate sufficient cash flow or liquidity to enable us to obtain the necessary aircraft acquisition financing to replace our current fleet, or to make required debt service payments related to our existing or anticipated future obligations. Even if we meet all required debt, lease and purchase obligations, the size of these long‑term obligations could negatively affect our financial condition, results of operations and the price of our common stock in many ways, including:

If we need additional capital and cannot obtain such capital on acceptable terms, or at all, we may be unable to realize our fleet replacement plans or take advantage of unanticipated opportunities.

Our business could be harmed if we lose the services of our key personnel.

Our business depends upon the efforts of our chief executive officer, Russell A. Childs, and our other key management and operating personnel. We may have difficulty replacing management or other key personnel who cease to be employed by us and, therefore, the loss of the services of any of these individuals could harm our business. We do not maintain key‑person insurance on any of our executive officers.

We may decrease our dividends and/or reduce the amount of stock repurchases in the future.

Historically, we have paid dividends and repurchased shares of our common stock in varying amounts. The future payment and amount of cash dividends and our future repurchases of shares of common stock, if any, and the number of shares of common stock we may repurchase will depend upon our financial condition and results of operations and other factors deemed relevant by our board of directors. There can be no assurance that we will continue our practice of paying dividends on our common stock or that we will have the financial resources to pay such dividends. There also can be no assurance that we will continue our practice of repurchasing shares of common stock or that we will have the financial resources to repurchase shares of common stock in the future.

In addition, repurchases of our common stock pursuant to our share repurchase program and any future dividends could affect our stock price and increase its volatility. The existence of a share repurchase program and any future dividends could cause our stock price to be higher than it would otherwise be and could potentially reduce the market liquidity for our stock. Additionally, our share repurchase program and any future dividends may reduce our cash reserves, which may impact our ability to finance future growth and to pursue possible future strategic opportunities and acquisitions. Further, our share repurchase program may fluctuate such that our cash flow may be insufficient to fully cover our share repurchases. Although our share repurchase program is intended to enhance long-term shareholder value, there is no assurance that it will do so because the market price of our common stock may decline below the levels at which we repurchased shares of stock and short-term stock price fluctuations could reduce the program’s effectiveness.

Disagreements regarding the interpretation of our code‑share agreements with our major airline partners could have an adverse effect on our operating results and financial condition.

Long‑term contractual agreements, such as our code‑share agreements, are subject to interpretation and disputes may arise under such agreements if the parties to an agreement apply different interpretations to that agreement. Those disputes may divert management time and resources from the core operation of the business, and may result in litigation, arbitration or other forms of dispute resolution.

In recent years we have experienced disagreements with our major airline partners regarding the interpretation of various provisions of our code‑share agreements. Some of those disagreements have resulted in litigation, and we may be subject to additional disputes and litigation in the future. Those disagreements have also required a significant amount of management time, financial resources and settlement negotiations of disputed matters.

To the extent that we experience disagreements regarding the interpretation of our code‑share or other agreements, we will likely expend valuable management time and financial resources in our efforts to resolve those disagreements. Those disagreements may result in litigation, arbitration, settlement negotiations or other proceedings. Furthermore, there can be no assurance that any or all of those proceedings, if commenced, would be resolved in our favor. An unfavorable result in any such proceeding could have adverse financial consequences or require us to modify our operations. Such disagreements and their consequences could have an adverse effect on our operating results and financial condition.

Provisions of our charter documents and code‑share agreements may limit the ability or desire of others to gain control of our company.

Our ability to issue shares of preferred and common stock without shareholder approval may have the effect of delaying or preventing a change in control and may adversely affect the voting and other rights of the holders of our common stock, even in circumstances where such a change in control would be viewed as desirable by most investors. The provisions of the Utah Control Shares Acquisitions Act may also discourage the acquisition of a significant interest in or control of our company. Additionally, our code‑share agreements contain termination and extension trigger provisions related to change in control type transactions that may have the effect of deterring a change in control of our company.

The adoption of new tax legislation or changes to existing tax laws and regulations could adversely affect our financial condition or results of operations.

The airline industry is one of the most heavily taxed industries in the United States. We are subject to tax laws and regulations of the U.S. federal, state and local governments as well as various non-U.S. jurisdictions. Potential changes in existing tax laws, including future regulatory guidance, may impact our effective tax rate and tax payments. There can be no assurance that changes in tax laws or regulations, both within the United States and the other jurisdictions in which we operate, will not materially and adversely affect our effective tax rate, tax payments, financial condition and results of operations. Similarly, changes in tax laws and regulations that impact our major airline partners, customers or the economy generally may also impact our financial condition and results of operations.

In addition, tax laws and regulations are complex and subject to varying interpretations, and any significant failure to comply with applicable tax laws and regulations in all relevant jurisdictions could give rise to substantial penalties and liabilities. Any changes in enacted tax laws, rules or regulatory or judicial interpretations; any adverse outcome in connection with tax audits in any jurisdiction; or any change in the pronouncements relating to accounting for income taxes could materially and adversely impact our effective tax rate, tax payments, financial condition and results of operations.

Risks Related to the Airline Industry

The occurrence of an aviation accident involving our aircraft would negatively impact our operations and financial condition.

An accident or incident involving one of our aircraft could result in significant potential claims of injured passengers and others, as well as repair or replacement of a damaged aircraft and its consequential temporary or permanent loss from service. In the event of an accident, our liability insurance may not be adequate to offset our exposure to potential claims and we may be forced to bear substantial losses from the accident. Substantial claims resulting from an accident in excess of our related insurance coverage would harm our operational and financial results. Moreover, any aircraft accident or incident, even if fully insured, could cause a public perception that our operations are less safe or reliable than other airlines.

Various factors may negatively impact demand for air travel in the United States.

As is the case for other airlines, our operations often are affected by delays, cancellations and other conditions caused by factors largely beyond our control. Factors that might negatively impact our operations include:

Increased labor costs, labor disputes and unionization of our workforces may adversely affect our ability to conduct our business and reduce our profitability.

Our business is labor intensive, requiring large numbers of pilots, flight attendants, mechanics and other personnel. Labor costs constitute a significant percentage of our total operating costs. For example, during the year ended December 31, 2018, our salary, wage and benefit costs constituted approximately 43.7% of our total operating costs. Increases in our labor costs could result in a material reduction in our earnings. Any new collective bargaining agreements entered into by other regional carriers with their work forces may also result in higher industry wages and increased pressure on us to increase the wages and benefits of our employees. Future agreements with represented employees may be on terms that are not as attractive as our current agreements or comparable to agreements entered into by our competitors.

SkyWest’s employees are represented by in-house associations; however, organizing efforts to join national unions among those employees occur from time to time. Such efforts will likely continue in the future and may ultimately result in some or all of our employees being represented by one or more national unions. If our employees were to unionize or be deemed to be represented by one or more national unions, negotiations with these unions could divert management attention and disrupt operations, which may result in increased operating expenses and may negatively impact our financial results. Moreover, we cannot predict the outcome of any future negotiations relating to union representation or collective bargaining agreements. Agreements reached in collective bargaining may increase our operating expenses and negatively impact our financial results.

We are subject to significant governmental regulation and potential regulatory changes.

All interstate air carriers, including SkyWest, are subject to regulation by the DOT, the FAA and other governmental agencies. Regulations promulgated by the DOT primarily relate to economic aspects of air service. The FAA requires operating, air worthiness and other certificates; approval of personnel who may engage in flight, maintenance or operation activities; record keeping procedures in accordance with FAA requirements; and FAA approval of flight training and retraining programs. We cannot predict whether we will be able to comply with all present and future laws, rules, regulations and certification requirements or that the cost of continued compliance will not have a material adverse effect on our operations. We incur substantial costs in maintaining our current certifications and otherwise complying with the laws, rules and regulations to which we are subject. A decision by the FAA to ground, or require time‑consuming inspections of or maintenance on, all or any of our aircraft for any reason may have a material adverse effect on our operations. In addition to state and federal regulation, airports and municipalities enact rules and regulations that affect our operations. From time to time, various airports throughout the country have considered limiting the use of smaller aircraft, such as our aircraft, at such airports. The imposition of any limits on the use of our aircraft at any airport at which we operate could have a material adverse effect on our operations.

We cannot predict the impact, of potential regulatory changes that may affect our business or the airline industry as whole including the potential impact of tariffs on aircraft deliveries. However, it is possible that these changes could adversely affect our business. Our business may be subject to additional costs or loss of government subsidies as a result of potential regulatory changes, which could have an adverse effect on our operations and financial results.

The airline industry is highly competitive and has undergone a period of consolidation and transition leaving fewer potential code‑share partners.

The airline industry is highly competitive. We not only compete with other regional airlines, some of which are owned by or operated as code‑share partners of major airlines, but we also face competition from low‑cost carriers and major airlines on many of our routes. Low‑cost carriers such as Southwest, Allegiant, Spirit and JetBlue among others, operate at many of our hubs, resulting in significant price competition. Additionally, a large number of other carriers operate at our hubs, creating intense competition. Certain of our competitors are larger and have significantly greater financial and other resources than we do. Moreover, federal deregulation of the industry allows competitors to rapidly enter our markets and to quickly discount and restructure fares. The airline industry is particularly susceptible to price discounting because airlines incur only nominal costs to provide service to passengers occupying otherwise unsold seats. Increased fare competition could adversely affect our operations and the price of our common stock. The airline industry has undergone substantial consolidation, including the mergers between Alaska and Virgin America Inc. in 2016,

American and US Airways Group Inc. in 2013, Southwest Airlines Co. and AirTran Holdings, Inc. in 2011, United and Continental Airlines, Inc. in 2010 and Delta and Northwest Airlines, Inc. in 2008. Any additional consolidation or significant alliance activity within the airline industry could limit the number of potential partners with whom we could enter into code‑share relationships and could have a material adverse effect on our relationships with our major airline partners.

Due, in part, to the dynamic nature of the airline industry, major airlines may also make other strategic changes such as changing or consolidating hub locations. If our major airline partners were to make changes such as these in their strategy and operations, our operations and financial results could be adversely impacted.

Terrorist activities or warnings have dramatically impacted the airline industry, and will likely continue to do so.

The terrorist attacks of September 11, 2001 and their aftermath have negatively impacted the airline industry in general, including our operations. The primary effects experienced by the airline industry include a substantial loss of passenger traffic and revenue. If additional terrorist attacks are launched against the airline industry, there will be lasting consequences of the attacks, which may include loss of life, property damage, increased security and insurance costs, increased concerns about future terrorist attacks, increased government regulation and airport delays due to heightened security. Additional terrorist attacks and the fear of such attacks could negatively impact the airline industry, and result in further decreased passenger traffic and yields, increased flight delays or cancellations associated with new government mandates, as well as increased security, fuel and other costs. We cannot provide any assurance that these events will not harm the airline industry generally or our operations or financial condition in particular.

ITEM 1B.  UNRESOLVED STAFF COMMENTS

None

ITEM 2.  PROPERTIES

Flight Equipment

As of December 31, 2018, our fleet available for scheduled service consisted of the following types of owned and leased aircraft:

Several factors may impact our fleet size throughout 2019 and thereafter, including contract expirations, lease expirations, growth opportunities and opportunities to transition to an alternative major airline partner. Below is our 2019 outlook on our fleet by aircraft type. Our actual future fleet size and/or mix of aircraft types will likely vary, and may vary materially, from our current fleet size.

 

 

 

Ground Facilities

SkyWest and SkyWest Airlines own or lease, and, as of December 31, 2018, ExpressJet owned or leased, the following principal properties:

SkyWest Facilities

SkyWest Airlines Facilities

ExpressJet Facilities (as of December 31, 2018 and retained by ExpressJet following our sale of ExpressJet in January 2019)

Our management deems the current facilities of SkyWest and SkyWest Airlines as being suitable to support existing operations and believes these facilities will be adequate for the foreseeable future.

ITEM 3.  LEGAL PROCEEDINGS

We are subject to certain legal actions which we consider routine to our business activities. As of December 31, 2018, our management believed, after consultation with legal counsel, that the ultimate outcome of such legal matters was not likely to have a material adverse effect on our financial position, liquidity or results of operations.

ITEM 4.  MINE SAFETY DISCLOSURES

The disclosure required by this item is not applicable.

PART II

ITEM 5.  MARKET FOR REGISTRANT’S COMMON EQUITY, RELATED STOCKHOLDER MATTERS AND ISSUER PURCHASES OF EQUITY SECURITIES

Market Information

Our common stock is traded on The Nasdaq Global Select Market under the symbol “SKYW.” As of February 12,  2019, there were approximately 745 stockholders of record of our common stock. Securities held of record do not include shares held in securities position listings. The transfer agent for our common stock is Zions First National Bank, Salt Lake City, Utah.

Dividends

During 2018, our Board of Directors declared regular quarterly dividends of $0.10 per share. During 2017, our Board of Directors declared regular quarterly dividends of $0.08 per share. We intend to continue to pay quarterly dividends subject to liquidity, capital availability and quarterly determinations that cash dividends are in the best interests of our shareholders.

Issuer Purchases of Equity Securities

Our Board of Directors has adopted a stock repurchase program which authorizes us to repurchase shares of our common stock in the public market or in private transactions, from time to time, at prevailing prices. As of December 31, 2018, our stock repurchase program authorized the repurchase of up to $100.0 million of our common stock. The following table summarizes our purchases under our stock repurchase program during the three months ended December 31, 2018:

 

 

On February 5, 2019, our Board of Directors approved a new share repurchase plan, pursuant to which we are authorized to repurchase up to $250 million of our common stock.  We are authorized to repurchase such shares of common stock at prevailing market prices in the open market, in privately negotiated transactions, or by other means in accordance with federal securities laws from time to time.  This authorization superseded our previous share repurchase plan approved in February 2017.

 

Stock Performance Graph

The following Performance Graph and related information shall not be deemed “soliciting material” or “filed” with the SEC, nor shall such information be incorporated by reference into any future filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended (the “Exchange Act”), except to the extent we specifically incorporate it by reference into such filing. 

The following graph compares the cumulative total shareholder return on our common stock over the five‑year period ended December 31, 2018, with the cumulative total return during such period of the Nasdaq Stock Market (U.S. Companies) and the Nasdaq Stock Market Transportation Index. The following graph assumes an initial investment of $100.00 with dividends reinvested. The stock performance shown on the graph below represents historical stock performance and is not necessarily indicative of future stock price performance.

 

 

 

ITEM 6.  SELECTED FINANCIAL DATA

The following selected financial and operating data should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” and our consolidated financial statements and related notes included elsewhere in this Report.

Selected Consolidated Financial Data (amounts in thousands, except per share data):

Selected Operating Data

 

ITEM 7.  MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

The following discussion and analysis presents factors that had a material effect on our results of operations during the years ended December 31, 2018, 2017 and 2016. Also discussed is our financial position as of December 31, 2018 and 2017. You should read this discussion in conjunction with our consolidated financial statements, including the notes thereto, appearing elsewhere in this Report or incorporated herein by reference. This discussion and analysis contains forward‑looking statements. Please refer to the sections of this Report entitled “Cautionary Statement Concerning Forward‑looking Statements” and “Item 1A. Risk Factors” for discussion of some of the uncertainties, risks and assumptions associated with these statements.

Overview

We have the largest regional airline operation in the United States. As of December 31, 2018, we offered scheduled passenger and air freight service with approximately 2,770 total daily departures to destinations in the United States, Canada, Mexico and the Caribbean. As of December 31, 2018, we had 596 aircraft available for scheduled service consisting of the following (which included 100 ERJ145s and 16 CRJ200s that ExpressJet operated for United and 10 Canadair CRJ700s that ExpressJet operated for American):

*As of December 31, 2018, these aircraft have been removed from service and are in the process of being returned under the applicable leasing arrangement or are aircraft transitioning between code-share agreements with our major airline partners.

Our business model is based on providing scheduled regional airline service under code-share agreements (commercial agreements between airlines that, among other things, allow one airline to use another airline’s flight designator codes on its flights) with our major airline partners.  Our success is principally centered on our ability to meet the needs of our major airline partners through providing a reliable and safe operation at attractive economics.  Over the last several years, our business has evolved as we have added 39 new E175 aircraft and five new CRJ900 aircraft to our fleet since December 31, 2017, and removed 12 ERJ145 aircraft, 20 CRJ700 aircraft and 16 CRJ900 aircraft that were operating under less profitable or unprofitable flying agreements.

 

We anticipate our fleet will continue to evolve, as we are scheduled to add 12 new E175 and 15 new CRJ900 aircraft to existing fixed-fee agreements by the end of 2021. We anticipate these new aircraft will be replacing older CRJ900 and CRJ700 aircraft currently operating under fixed-fee agreements. Our primary objective in the fleet changes is to improve our profitability by adding new aircraft to fixed-fee agreements at improved economics, including the E175 aircraft, while removing aircraft that were operating under less profitable or unprofitable arrangements.

 

As of December 31, 2018, ExpressJet operated 100 ERJ145 aircraft and 16 CRJ200 aircraft under fixed-fee agreements with United and 10 CRJ700 aircraft under a fixed-fee agreement with American.  On January 22, 2019, we completed the sale of ExpressJet. In conjunction with the sale of ExpressJet, we retained ownership of the 16 CRJ200 aircraft and the 10 CRJ700 aircraft operated by ExpressJet as of December 31, 2018.  ExpressJet retained operation of the 100 ERJ145 aircraft that ExpressJet leased from United. We agreed to lease the 16 CRJ200 aircraft to ExpressJet for up to a five-year period.  We are pursuing alternative uses of the 10 CRJ700 aircraft, including but not limited to, using the aircraft under fixed-fee agreements or leasing the aircraft or related engines to third parties.

For the year ended December 31, 2018, approximately 48.6% of our aircraft in scheduled service were operated for United, approximately 33.4% were operated for Delta, approximately 12.6% were operated for American and approximately 5.4% were operated for Alaska.

Historically, multiple contractual relationships with major airlines have enabled us to reduce our reliance on any single major airline code and to enhance and stabilize operating results through a mix of fixed‑fee arrangements and our prorate flying arrangements. For the year ended December 31, 2018, contract flying revenue and prorate revenue represented approximately 84.3% and 15.7%, respectively, of our total flying agreements revenue. On contract routes, the major airline partner controls scheduling, ticketing, pricing and seat inventories and we are compensated by the major airline partner at contracted rates based on completed block hours (measured from takeoff to landing, including taxi time), flight departures and other operating measures.

Our financial and operating results for the years ended December 31, 2016, 2017 and 2018, and our financial position as of December 31, 2017 and 2018 contained in this Report, include the financial results and position of ExpressJet for those respective periods. 

Financial Highlights

We had total operating revenues of $3.2 billion for the year ended December 31, 2018, a 3.2% increase, compared to total operating revenues of $3.1 billion for the year ended December 31, 2017. We had a net income of $280.4 million, or $5.30 per diluted share, for the year ended December 31, 2018, compared to net income of $428.9 million, or $8.08 per diluted share, for the year ended December 31, 2017. Our results for 2017 included a $246.8 million benefit related to the revaluation of our net deferred tax liability and other tax liabilities in accordance with the Tax Cuts and Jobs Act that was enacted into law in December 2017.

 

The significant items affecting our financial performance during the year ended December 31, 2018 are outlined below:

 

Revenue

The number of aircraft we have in scheduled service and the number of block hours we generate on our flights are primary drivers to our flying agreements revenue under our fixed-fee arrangements.  During 2018, we had a net increase in the number of aircraft operating under fixed-fee agreements. As summarized under the Fleet Activity section below, from December 31, 2017 to December 31, 2018, we removed 48 aircraft from service that were operating under less profitable flying contracts and added 49 aircraft to new or existing fixed-fee arrangements at improved economics.  The number of aircraft available for scheduled service increased from 595 aircraft at December 31, 2017 to 596 at December 31, 2018.  Our completed block hours decreased 4.5% primarily due to the timing of our fleet transition during 2018. The majority of the aircraft removed from service during 2018 were removed during the first half of the year, whereas the majority of the aircraft added into service were added during the second half of the year.

 

Despite the reduction in our block hour production since 2017, our total flying agreements revenue increased 3.2% from 2017 to 2018 primarily due to higher compensation we earned on aircraft, including new aircraft added in 2018, partially offset by a decrease in revenue associated with the aircraft removed from our fleet.

 

Operating Expenses

The increase in our operating expense from 2017 to 2018 of $13.0 million, or 0.5%, was primarily related to increased compensation paid to our crews since December 31, 2017, an increase in our average fuel costs per gallon on our prorate flying arrangements and an increase in other operating expenses, including pilot recruitment and training costs. Additional details regarding the increase in our operating expenses are described in the section of this Report entitled “Results of Operations.”

 

Fleet Activity

 The following table summarizes our fleet activity for 2018:

 

 

During 2018, we took delivery of 39 new E175 aircraft and five new CRJ900 aircraft and placed the aircraft into service under fixed-fee flying agreements.  We removed 16 CRJ900 aircraft from service and returned the aircraft to the lessor.  We also removed 20 CRJ700 aircraft from service during 2018 that we either returned to the lessor, are in the process of transitioning to another major airline partner, or are pursuing alternative uses of the aircraft, including, but not limited to, leasing the aircraft or related engines to third parties.  The five CRJ200 aircraft added to service during 2018 were temporarily out of service at December 31, 2017.  We removed 12 ERJ145s from service and returned the aircraft to the lessor.  

 

Critical Accounting Policies and Estimates

Our significant accounting policies are summarized in Note 1 to our Consolidated Financial Statements included in Item 8 of this Report. Critical accounting policies are those policies that are most important to the preparation of our consolidated financial statements and require management’s subjective and complex judgments due to the need to make estimates about the effect of matters that are inherently uncertain. Our critical accounting policies relate to revenue recognition, aircraft maintenance, aircraft leases, impairment of long‑lived assets, stock‑based compensation expense and fair value as discussed below. The application of these accounting policies involves the exercise of judgment and the use of assumptions as to future uncertainties and, as a result, actual results will likely differ, and could differ materially, from such estimates.

Revenue Recognition

Flying agreements and airport customer service and other revenues are recognized when service is provided. Under our fixed-fee and prorate flying agreements with our major airline partners, revenue is considered earned when each flight is completed. A portion of our compensation under our fixed-fee flying agreements is designed to reimburse us for the use of the aircraft we provide under such agreements. This compensation is deemed to be lease revenue, inasmuch as the agreements identify the “right of use” or a specific type and number of aircraft over the agreement term.  The amount of compensation deemed to be lease revenue is determined from the agreed upon rates for the use of the aircraft included in each fixed-fee agreement, which we believe approximates fair value for the aircraft leases. Under our airport customer service agreements, revenue is considered earned when each flight we provide customer service for departs. Our agreements with our major airline partners contain certain provisions pursuant to which the parties could terminate the respective agreement, subject to certain rights of the other party, if certain performance criteria are not maintained. Our revenues could be impacted by a number of factors, including changes to the applicable code‑share agreements, contract modifications resulting from contract renegotiations and our ability to earn incentive payments contemplated under applicable agreements. In the event contracted rates are not finalized at a quarterly or annual financial statement date, we record that period’s revenues based on the lower of the prior period’s approved rates or our estimate of rates that will be implemented upon completion of negotiations. Also, in the event we have a reimbursement dispute with a major airline partner at a quarterly or annual financial statement date, we evaluate the dispute under established revenue recognition criteria and, provided the revenue recognition criteria have been met, we recognize revenue for that period based on our estimate of the resolution of the dispute. Accordingly, we are required to exercise judgment and use assumptions in the application of our revenue recognition policy.

 Maintenance

For the majority of our engines, we have an agreement with a third‑party vendor to provide long‑term engine maintenance covering scheduled and unscheduled engine repairs, including engine overhauls, operating under our fixed‑rate engine contracts (a “Power-by-the-Hour Agreement”). Under the terms of the Power-by-the-Hour Agreement,

we are obligated to pay a set dollar amount per engine hour flown on a monthly basis and the vendor assumes the obligation to repair the engines at no additional cost to us, subject to certain specified exclusions. Thus, under the Power-by-the-Hour Agreement, we expense the engine maintenance costs as flight hours are incurred on the engines and using the contractual rate set forth in the agreement.

For engines not covered under a Power-by-the-Hour-Agreement we use the direct‑expense method of accounting for our regional jet aircraft engine overhaul costs. Under this method, the maintenance liability is not recorded until the maintenance services are performed.

Aircraft Leases

As of December 31, 2018, our fleet of aircraft in scheduled service included 245 aircraft under lease (including 108 aircraft leased by ExpressJet). In order to determine the proper classification of our leased aircraft as either operating leases or capital leases, we must make certain estimates at the inception of the lease relating to the economic useful life and the fair value of an asset as well as select an appropriate discount rate to be used in discounting future lease payments. These estimates are utilized by management in making computations as required by existing accounting standards that determine whether the lease is classified as an operating lease or a capital lease. All of our aircraft leases have been classified as operating leases, which results in rental payments being charged to expense over the terms of the related leases. Under some of our fixed-fee arrangements, our major airline partners may acquire aircraft from third-parties and lease the aircraft to us for a de minimis amount, and in such cases, no related lease revenue or lease expense is recognized. Under the majority of our operating leases, we are required to meet half-time lease return conditions with the aircraft, which presumes at least 50 percent of the eligible flight time for certain components since the last overhaul remains when the aircraft is returned to the lessor. A liability for probable lease return costs is recorded after the aircraft has completed its last maintenance cycle prior to being returned. Additionally, operating leases are not reflected in our consolidated balance sheet and accordingly, neither a lease asset nor an obligation for future lease payments is reflected in our consolidated balance sheets. See “Recent Accounting Pronouncements” set forth below for a discussion of a new accounting standard that is likely to have an impact on our aircraft lease accounting beginning in 2019. 

 

Long‑Lived Assets

 

As of December 31, 2018, we had approximately $5.0 billion of property and equipment and related assets net of accumulated depreciation. In accounting for these long‑lived, we make estimates about the expected useful lives of the assets, the expected residual values of certain of these assets, and the potential for impairment based on the fair value of the assets and the cash flows they generate. Factors indicating potential impairment include, but are not limited to, significant decreases in the market value of the long‑lived assets, a significant change in the condition of the long‑lived assets and operating cash flow losses associated with the use of the long‑lived assets. When considering whether or not impairment of long‑lived assets exists, we group similar assets together at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities and compare the undiscounted cash flows for each asset group to the net carrying amount of the assets supporting the asset group. Asset groupings are done at the fleet type or contract level. We did not have any impairment charges during the year ended December 31, 2018.

Stock‑Based Compensation Expense

Restricted stock units (“RSUs”) are awarded to eligible employees and entitle the grantee to receive shares of common stock at the end of the vest period.  Performance Share Units (“PSUs”) are awarded to certain employees to receive shares of common stock if specific performance targets are achieved. At the end of each performance period, the number of shares awarded can range from 0% to 200% of the original 2018 and 2017 grant amounts for performance share units and can range from 0% to 150% of the original 2016 grant amount for performance shares, depending on the performance against the pre-established targets. The fair value of the RSUs and PSUs are based on the stock price as of the date of grant and “cliff vest” after three years. We are required to use judgment and estimates in determining compensation expense for the PSUs based on projected performance compared to the pre-established targets over the measurement period for unvested PSU awards. 

Fair value

We hold certain assets that are required to be measured at fair value in accordance with U.S. Generally Accepted Accounting Principles. We determined fair value of these assets based on the following three levels of inputs:

 

 

We utilize several valuation techniques in order to assess the fair value of our financial assets and liabilities. Our cash and cash equivalents primarily utilize quoted prices in active markets for identical assets or liabilities.

Recent Accounting Pronouncements

See Note 1 to the Consolidated Financial Statements included in Item 8 of this Report for a description of recent accounting pronouncements.

 

Results of Operations

2018 Compared to 2017

Operational Statistics. The following table sets forth our major operational statistics and the associated percentages of change for the periods identified below. The decrease in block hours, departures and passengers carried during the year ended December 31, 2018, compared to the year ended December 31, 2017, was primarily due to the timing of our fleet transition during 2018.  Although our total number of aircraft in service did not significantly change from December 31, 2017 to December 31, 2018, the majority of the aircraft removed from service were removed during the first half of 2018 while the majority of the aircraft added into service were added during the second half of 2018.

 

 

Operating Revenues

 

The following table summarizes our operating revenue for the periods indicated (dollar amounts in thousands):

 

 

Flying agreements revenue primarily consists of revenue earned on flights we operate under our capacity purchase agreements and prorate agreements with our major airline partners.  Airport customer service and other revenues primarily consist of revenue earned from providing airport counter, gate and ramp services.  Changes in our flying agreements revenue are summarized below (dollar amounts in thousands).

 

 

The increase in “Capacity purchase agreements revenue: flight operations” of $50.7 million was primarily due to incremental revenue generated from 39 new E175 aircraft and five new CRJ900 aircraft added to our fleet and economic improvements made to certain existing fixed-fee agreements that were renewed or extended since December 31, 2017, partially offset by the timing of the removal of 48 ERJ145, CRJ700 and CRJ900 aircraft from flying arrangements with a lower revenue per aircraft since December 31, 2017.  The decrease in “Capacity purchase agreement revenue: aircraft lease” of $19.8 million was primarily due to the timing and number of leased aircraft removed from fixed-fee contracts for the year ended December 31, 2017 compared to the year ended December 31, 2018.  The increase in prorate agreement revenue of $60.3 million was primarily due to the incremental revenue generated from seven CRJ200 aircraft added to our prorate agreements and new prorate agreements at improved economics since December 31, 2017.

 

The $7.9 million increase in airport customer service and other revenues was primarily related to a combination of an increase in volume of airport service agreements and contract rate increases on agreements that were renewed since December 31, 2017.

 

Individual expense components attributable to our operations are set forth in the following table (dollar amounts in thousands).

 

Salaries, wages and benefits. The $9.5 million, or 0.8%, decrease in salaries, wages and benefits during the year ended December 31, 2018, compared to the year ended December 31, 2017,  was primarily due to higher flight crew compensation costs resulting from labor agreements executed during the second half of 2018, which was partially offset by a decrease in direct labor costs resulting from a reduction in departures and block hours.

Aircraft maintenance, materials and repairs. The $23.2 million, or 4.0%, decrease in aircraft maintenance expense during the year ended December 31, 2018, compared to the year ended December 31, 2017,  was primarily due to a decrease in scheduled maintenance events and the replacement and repair of aircraft parts and components partially offset by an increase in the percentage of our fleet that is under long-term Power-by-the-Hour maintenance agreements, including the additional 39 E175 aircraft added since December 31, 2017.  

Depreciation and amortization.  The $41.8 million, or 14.3%, increase in depreciation and amortization expense during the year ended December 31, 2018, compared to the year ended December 31, 2017, was primarily due to the purchase of 39 additional E175 aircraft and related long-lived aircraft parts in 2018.  

Aircraft rentals.  The $60.9 million, or 28.2%, decrease in aircraft rentals during the year ended December 31, 2018, compared to the year ended December 31, 2017, was primarily due to a decrease in leased aircraft from 319 leased aircraft for the year ended December 31, 2017, to 260 leased aircraft for the year ended December 31, 2018.

Aircraft fuel.  The $32.5 million, or 38.2%, increase in fuel cost during the year ended December 31, 2018, compared to the year ended December 31, 2017, was primarily due to an increase in our average fuel cost per gallon from $2.06 for the year ended December 31, 2017 to $2.60 for the year ended December 31, 2018, along with an increase in the number of prorate flights we operated and the corresponding additional gallons of fuel we purchased. We purchase and incur expense for all fuel on flights operated under our prorate agreements. All fuel costs incurred under our fixed-fee contracts are either purchased directly by our major airline partner, or if purchased by us, we record the direct reimbursement as a reduction to our fuel expense. The following table summarizes the gallons of fuel we purchased under our prorate agreements, for the periods indicated:

 

 

Airport-related expenses.    Airport-related expenses include airport-related customer service costs such as outsourced airport gate and ramp agent services, airport security fees, passenger interruption costs, deicing, landing fees and station rents (our employee customer service labor costs are reflected in salaries, wages and benefits). The $8.8 million, or 7.4%, decrease in airport-related expenses during the year ended December 31, 2018, compared to the year