Item 1. BUSINESS.

Overview

United Continental Holdings, Inc. (together with its consolidated subsidiaries, "UAL" or the "Company") is a holding company and its principal, wholly-owned subsidiary is United Airlines, Inc. (together with its consolidated subsidiaries, "United"). As UAL consolidates United for financial statement purposes, disclosures that relate to activities of United also apply to UAL, unless otherwise noted. United's operating revenues and operating expenses comprise nearly 100% of UAL's revenues and operating expenses. In addition, United comprises approximately the entire balance of UAL's assets, liabilities and operating cash flows. When appropriate, UAL and United are named specifically for their individual contractual obligations and related disclosures and any significant differences between the operations and results of UAL and United are separately disclosed and explained. We sometimes use the words "we," "our," "us," and the "Company" in this report for disclosures that relate to all of UAL and United.

UAL was incorporated under the laws of the State of Delaware on December 30, 1968. Our principal executive office is located at 233 South Wacker Drive, Chicago, Illinois 60606 (telephone number (872) 825-4000).

The Company's website is located at www.united.com and its investor relations website is located at ir.united.com. The information contained on or connected to the Company's websites is not incorporated by reference into this Annual Report on Form 10-K and should not be considered part of this or any other report filed with the U.S. Securities and Exchange Commission ("SEC"). The Company's filings with the SEC, including annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and all amendments to those reports, as well as UAL's proxy statement for its annual meeting of stockholders, are accessible without charge on the Company's investor relations website, as soon as reasonably practicable, after such material is electronically filed with, or furnished to, the SEC. Such filings are also available on the SEC's website at www.sec.gov.

Operations

The Company transports people and cargo throughout North America and to destinations in Asia, Europe, the Middle East and Latin America. UAL, through United and its regional carriers, operates more than 4,800 flights a day to 353 airports across five continents, with hubs at Newark Liberty International Airport ("Newark"), Chicago O'Hare International Airport ("Chicago O'Hare"), Denver International Airport ("Denver"), George Bush Intercontinental Airport ("Houston Bush"), Los Angeles International Airport ("LAX"), A.B. Won Pat International Airport ("Guam"), San Francisco International Airport ("SFO") and Washington Dulles International Airport ("Washington Dulles").

All of the Company's domestic hubs are located in large business and population centers, contributing to a large amount of "origin and destination" traffic. The hub and spoke system allows us to transport passengers between a large number of destinations with substantially more frequent service than if each route were served directly. The hub system also allows us to add service to a new destination from a large number of cities using only one or a limited number of aircraft. As discussed under Alliances below, United is a member of Star Alliance, the world's largest alliance network.

Regional. The Company has contractual relationships with various regional carriers to provide regional aircraft service branded as United Express. This regional service complements our operations by carrying traffic that connects to our hubs and allows flights to smaller cities that cannot be provided economically with mainline aircraft. Republic Airlines ("Republic"), Champlain Enterprises, LLC d/b/a CommutAir ("CommutAir"), ExpressJet Airlines ("ExpressJet"), GoJet Airlines ("GoJet"), Mesa Airlines ("Mesa"), SkyWest Airlines ("SkyWest"), Air Wisconsin Airlines ("Air Wisconsin"), and Trans States Airlines ("Trans States") are all regional carriers that operate with capacity contracted to United under capacity purchase agreements ("CPAs"). Under these CPAs, the Company pays the regional carriers contractually agreed fees (carrier costs) for operating these flights plus a variable reimbursement (incentive payment for operational performance) based on agreed performance metrics, subject

to annual adjustments. The fees for carrier costs are based on specific rates for various operating expenses of the regional carriers, such as crew expenses, maintenance and aircraft ownership, some of which are multiplied by specific operating statistics (e.g., block hours, departures), while others are fixed monthly amounts. Under these CPAs, the Company is responsible for all fuel costs incurred, as well as landing fees and other costs, which are either passed through by the regional carrier to the Company without any markup or directly incurred by the Company, and, in some cases, the Company owns or leases some or all of the aircraft subject to the CPA, and leases or subleases, as applicable, such aircraft to the regional carrier. In return, the regional carriers operate the capacity of the aircraft included within the scope of such CPA exclusively for United, on schedules determined by the Company. The Company also determines pricing and revenue management, assumes the inventory and distribution risk for the available seats and permits mileage accrual and redemption for regional flights through its MileagePlus® loyalty program.

Alliances. United is a member of Star Alliance, a global integrated airline network and the largest and most comprehensive airline alliance in the world. As of January 1, 2019, Star Alliance carriers served over 1,300 airports in 193 countries with 18,800 daily departures. Star Alliance members, in addition to United, are Adria Airways, Aegean Airlines, Air Canada, Air China, Air India, Air New Zealand, All Nippon Airways ("ANA"), Asiana Airlines, Austrian Airlines, Aerovías del Continente Americano S.A. ("Avianca"), Avianca Brasil, Brussels Airlines, Copa Airlines, Croatia Airlines, EGYPTAIR, Ethiopian Airlines, EVA Air, LOT Polish Airlines, Lufthansa, SAS Scandinavian Airlines, Shenzhen Airlines, Singapore Airlines, South African Airways, SWISS, TAP Air Portugal, THAI Airways International and Turkish Airlines. In addition to its members, Star Alliance includes Shanghai-based Juneyao Airlines as a connecting partner.

United has a variety of bilateral commercial alliance agreements and obligations with Star Alliance members, addressing, among other things, reciprocal earning and redemption of frequent flyer miles, access to airport lounges and, with certain Star Alliance members, codesharing of flight operations (whereby one carrier's selected flights can be marketed under the brand name of another carrier). In addition to the alliance agreements with Star Alliance members, United currently maintains independent marketing alliance agreements with other air carriers, including Aeromar, Aer Lingus, Air Dolomiti, Azul Linhas Aéreas Brasileiras S.A. ("Azul"), Boutique Air, Cape Air, Eurowings, Hawaiian Airlines, and Silver Airways. In addition to the marketing alliance agreements with air partners, United also offers a train-to-plane codeshare and frequent flyer alliance with Amtrak from Newark on select city pairs in the northeastern United States.

United also participates in four passenger joint business arrangements ("JBAs"): one with Air Canada and the Lufthansa Group (which includes Lufthansa and its affiliates Austrian Airlines, Brussels Airlines, Eurowings and SWISS) covering transatlantic routes, one with ANA covering certain transpacific routes, one with Air New Zealand covering certain routes between the United States and New Zealand and one with Avianca and Copa Airlines, which, upon receipt of regulatory approvals will cover routes between the United States and Central and South America, excluding Brazil. These passenger JBAs enable the participating carriers to integrate the services they provide in the respective regions, capturing revenue synergies and delivering enhanced customer benefits, such as highly competitive flight schedules, fares and services. United also participates in cargo JBAs with ANA for transpacific cargo services and with Lufthansa for transatlantic cargo services. These cargo JBAs offer expanded and more seamless access to cargo space across the carriers' respective combined networks.

Loyalty Program. United's MileagePlus loyalty program builds customer loyalty by offering awards, benefits and services to program participants. Members in this program earn miles for flights on United, United Express, Star Alliance members and certain other airlines that participate in the program. Members can also earn miles by purchasing the goods and services of our network of non-airline partners, such as domestic and international credit card issuers, retail merchants, hotels and car rental companies. Members can redeem miles for free (other than taxes and government imposed fees), discounted or upgraded travel and non-travel awards.

United has an agreement with Chase Bank USA, N.A. ("Chase"), pursuant to which members of United's MileagePlus loyalty program who are residents of the United States can earn miles for making purchases using a MileagePlus credit card issued by Chase (the "Co-Brand Agreement"). The Co-Brand Agreement also provides for joint marketing and other support for the MileagePlus credit card and provides Chase with other benefits such as permission to market to the Company's customer database.

Approximately 5.6 million and 5.4 million MileagePlus flight awards were used on United in 2018 and 2017, respectively. These awards represented 7.1% and 7.5% of United's total revenue passenger miles in 2018 and 2017, respectively. Total miles redeemed for flights on United in 2018, including class-of-service upgrades, represented approximately 86% of the total miles redeemed. In addition, excluding miles redeemed for flights on United, MileagePlus members redeemed miles for approximately 2.4 million other awards in 2018 as compared to 2.3 million other awards in 2017. These awards include United Club memberships, car and hotel awards, merchandise and flights on other air carriers.

Aircraft Fuel. The table below summarizes UAL's aircraft fuel consumption and expense during the last three years.

Our operational and financial results can be significantly impacted by changes in the price and availability of aircraft fuel. To provide adequate supplies of fuel, the Company routinely enters into purchase contracts that are customarily indexed to market prices for aircraft fuel, and the Company generally has some ability to cover short-term fuel supply and infrastructure disruptions at certain major demand locations. The price of aircraft fuel has fluctuated substantially in the past several years. The Company's current strategy is to not enter into transactions to hedge its fuel consumption, although the Company regularly reviews its strategy based on market conditions and other factors.

Third-Party Business. United generates third-party business revenue that includes frequent flyer award non-air redemptions, maintenance services, catering and ground handling. Third-party business revenue is recorded in Other operating revenue. Expenses associated with third-party business, except non-air redemptions, are recorded in Other operating expenses. Non-air redemptions expenses are recorded to Other operating revenue.

Distribution Channels. The Company's airline seat inventory and fares are distributed through the Company's direct channels, traditional travel agencies and on-line travel agencies. The use of the Company's direct sales website, www.united.com, the Company's mobile applications and alternative distribution systems provides the Company with an opportunity to de-commoditize its services, better present its content, make more targeted offerings, better retain its customers, enhance its brand and lower its ticket distribution costs. Agency sales are primarily sold using global distribution systems ("GDS"). United has developed and expects to continue to develop capabilities to sell certain ancillary products through the GDS channel to provide an enhanced buying experience for customers who purchase in that channel.

Industry Conditions

Domestic Competition. The domestic airline industry is highly competitive and dynamic. The Company's competitors consist primarily of other airlines and, to a certain extent, other forms of transportation. Currently, any U.S. carrier deemed fit by the U.S. Department of Transportation (the "DOT") is largely free to operate scheduled passenger service between any two points within the United States. Competition can be direct, in the form of another carrier flying the exact non-stop route, or indirect, where a carrier serves the same two cities non-stop from an alternative airport in that city or via an itinerary requiring a connection at another airport. Air carriers' cost structures are not uniform and there are numerous factors influencing cost structure. Carriers with lower costs may offer lower fares to passengers, which could have a potential negative impact on the Company's revenues. Decisions on domestic pricing are based on intense competitive pressure exerted on the Company by other U.S. airlines. In order to remain competitive and maintain passenger traffic levels, we often find it necessary to match competitors' discounted fares. Since we compete in a dynamic marketplace, attempts to generate additional revenue through increased fares oftentimes fail.

International Competition. Internationally, the Company competes not only with U.S. airlines, but also with foreign carriers. International competition has increased and may continue to increase in the future as a result of airline mergers and acquisitions, JBAs, alliances, restructurings, liberalization of aviation bilateral agreements and new or increased service by competitors, including government subsidized competitors from certain Middle East countries. Competition on international routes is subject to varying degrees of governmental regulation. The Company's ability to compete successfully with non-U.S. carriers on international routes depends in part on its ability to generate traffic to and from the entire United States via its integrated domestic route network and its ability to overcome business and operational challenges across its network worldwide. Foreign carriers currently are prohibited by U.S. law from carrying local passengers between two points in the United States and the Company generally experiences comparable restrictions in foreign countries. Separately, "fifth freedom rights" allow the Company to operate between points in two different foreign countries and foreign carriers may also have fifth freedom rights between the U.S. and another foreign country. In the absence of fifth freedom rights, or some other extra-bilateral right to conduct operations between two foreign countries, U.S. carriers are constrained from carrying passengers to points beyond designated international gateway cities. To compensate partially for these structural limitations, U.S. and foreign carriers have entered into alliances, immunized JBAs and marketing arrangements that enable these carriers to exchange traffic between each other's flights and route networks. See Alliances, above, for additional information.

Seasonality. The air travel business is subject to seasonal fluctuations. Historically, demand for air travel is higher in the second and third quarters, driving higher revenues, than in the first and fourth quarters, which are periods of lower travel demand.

Industry Regulation

Domestic Regulation

All carriers engaged in air transportation in the United States are subject to regulation by the DOT. Absent an exemption, no air carrier may provide air transportation of passengers or property without first being issued a DOT certificate of public convenience and necessity. The DOT also grants international route authority, approves international codeshare arrangements and regulates methods of competition. The DOT regulates consumer protection and maintains jurisdiction over advertising, denied boarding compensation, tarmac delays, baggage liability and other areas and may add additional expensive regulatory burdens in the future. The DOT has launched investigations or claimed rulemaking authority to regulate commercial agreements among carriers or between carriers and third parties in a wide variety of contexts.

Airlines are also regulated by the Federal Aviation Administration (the "FAA"), an agency within the DOT, primarily in the areas of flight safety, air carrier operations and aircraft maintenance and airworthiness. The FAA issues air carrier operating certificates and aircraft airworthiness certificates, prescribes maintenance procedures, oversees airport operations, and regulates pilot and other employee training. From time to time, the FAA issues directives that require air carriers to inspect or modify aircraft and other equipment, potentially causing the Company to incur substantial, unplanned expenses. The airline industry is also subject to numerous other federal laws and regulations. The U.S. Department of Homeland Security ("DHS") has jurisdiction over virtually every aspect of civil aviation security. The Antitrust Division of the U.S. Department of Justice ("DOJ") has jurisdiction over certain airline competition matters. The U.S. Postal Service has authority over certain aspects of the transportation of mail by airlines. Labor relations in the airline industry are generally governed by the Railway Labor Act ("RLA"), a federal statute. The Company is also subject to investigation inquiries by the DOT, FAA, DOJ, DHS, the U.S. Food and Drug Administration ("FDA"), the U.S. Department of Agriculture ("USDA") and other U.S. and international regulatory bodies.

Airport Access. Access to landing and take-off rights, or "slots," at several major U.S. airports served by the Company are subject to government regulation. Federally-mandated domestic slot restrictions that limit operations and regulate capacity currently apply at three airports: Reagan National Airport in Washington, D.C. ("Reagan National"), John F. Kennedy International Airport and LaGuardia Airport in the New York City metropolitan region ("LaGuardia"). Of these three airports, United currently operates at two: Reagan National and LaGuardia. Additional restrictions on takeoff and landing slots at these and other airports may be implemented in the future and could affect the Company's rights of ownership and transfer as well as its operations.

Legislation. The airline industry is subject to legislative actions (or inactions) that may have an impact on operations and costs. In 2018, the U.S. Congress approved a five-year reauthorization for the FAA, which encompasses significant aviation tax and policy-related issues. The law includes a range of policy changes related to airline customer service and aviation safety which, depending on how they are implemented, could impact our operations and costs. Additionally, the U.S. Congress may fail to continue to fund the operations of one or more federal government agencies which could negatively impact the Company and the airline industry.

Catering Operations. The Company owns and operates catering kitchens at airports in Denver, Cleveland, Newark, Houston, and Honolulu, which prepare ready-to-eat food for United flights. Some of the Company's kitchens also prepare ready-to-eat food for other domestic and international airlines. These operations are subject to regulation by the FDA and the USDA, as well as other federal, state, and local regulatory agencies. The FDA has begun enforcing the Federal Food Safety Modernization Act which requires all food manufacturers to implement stringent risk-based preventive controls. As a result, ready-to-eat catering operations are a focus of enhanced scrutiny by the FDA with inspections and greater enforcement.

International Regulation

International air transportation is subject to extensive government regulation. In connection with the Company's international services, the Company is regulated by both the U.S. government and the governments of the foreign countries the Company serves. In addition, the availability of international routes to U.S. carriers is regulated by aviation agreements between the U.S. and foreign governments, and in some cases, fares and schedules require the approval of the DOT and/or the relevant foreign governments.

Legislation. Foreign countries are increasingly enacting passenger protection laws, rules and regulations that meet or exceed U.S. requirements. In cases where this activity exceeds U.S. requirements, additional burden and liability may be placed on the Company. Certain countries have regulations requiring passenger compensation and/or enforcement penalties from the Company in addition to changes in operating procedures due to canceled and delayed flights.

Airport Access. Historically, access to foreign markets has been tightly controlled through bilateral agreements between the U.S. and each foreign country involved. These agreements regulate the markets served, the number of carriers allowed to serve each market and the frequency of carriers' flights. Since the early 1990s, the U.S. has pursued a policy of "Open Skies" (meaning all U.S.-flag carriers have access to the destination), under which the U.S. government has negotiated a number of bilateral agreements allowing unrestricted access between U.S. and foreign markets. Currently, there are more than 100 Open Skies agreements in effect. However, even with Open Skies, many of the airports that the Company serves in Europe, Asia and Latin America maintain slot controls. A large number of these slot controls exist due to congestion, environmental and noise protection and reduced capacity due to runway and air traffic control ("ATC") construction work, among other reasons. London Heathrow International Airport, Frankfurt Rhein-Main Airport, Shanghai Pudong International Airport, Beijing Capital International Airport, Sao Paulo Guarulhos International Airport and Tokyo Haneda International Airport are among the most restrictive foreign airports due to slot and capacity limitations.

The Company's ability to serve some foreign markets and expand into certain others is limited by the absence of aviation agreements between the U.S. government and the relevant foreign governments. Shifts in U.S. or foreign government aviation policies may lead to the alteration or termination of air service agreements. Depending on the nature of any such change, the value of the Company's international route authorities and slot rights may be materially enhanced or diminished. Similarly, foreign governments control their airspace and can restrict our ability to overfly their territory, enhancing or diminishing the value of the Company's existing international route authorities and slot rights.

Environmental Regulation

The airline industry is subject to increasingly stringent federal, state, local and international environmental requirements, including those regulating emissions to air, water discharges, safe drinking water and the use and management of hazardous substances and wastes.

Climate Change. There is an increasing global regulatory focus on greenhouse gas ("GHG") emissions and their potential impacts relating to climate change. Initiatives to regulate GHG emissions from aviation had previously been adopted by the European Union ("EU") in 2009, but applicability to flights arriving or departing from airports outside the EU have been postponed several times. In December 2017, the European Parliament voted to extend exemptions for extra-EU flights until December 2023 in order to align the extension date with the completion of the pilot phase of the International Civil Aviation Organization's ("ICAO") Carbon Offsetting and Reduction Scheme for International Aviation ("CORSIA"). CORSIA, which was adopted in October 2016, is intended to create a single global market-based measure to achieve carbon-neutral growth for international aviation after 2020, which can be achieved through airline purchases of carbon offset credits. Certain CORSIA program details remain to be developed and could potentially be affected by political developments in participating countries or the results of the pilot phase of the program, and thus the impact of CORSIA cannot be fully predicted. However, CORSIA is expected to increase operating costs for airlines that operate internationally. In 2016, ICAO also adopted a carbon dioxide ("CO2") emission standard for aircraft. In 2016, the U.S. Environmental Protection Agency ("EPA") commenced procedural steps necessary to adopt its own standard, but the timing of further action by the EPA is unknown. While the precise timing and final form of these various programs and requirements continue to evolve, in 2018, the Company announced a pledge to reduce its greenhouse gas emissions by 50 percent relative to 2005 levels by the year 2050 and is taking various actions that are expected to help reduce its CO2 emissions over time such as improving fuel efficiency, fleet renewal, aircraft retrofits and the commercialization of aviation alternative fuels.

Other Regulations. Our operations are subject to a variety of other environmental laws and regulations both in the United States and internationally. These include noise-related restrictions on aircraft types and operating times and state and local air quality initiatives which have, or could in the future, result in curtailments in services, increased operating costs, limits on expansion, or further emission reduction requirements. Certain airports and/or governments, both domestically and internationally, either have or are seeking to establish environmental fees and other requirements applicable to carbon emissions, local air quality pollutants and/or noise. The implementation of state plans to achieve national standards for ozone is expected to result in restrictions on mobile sources such as cars, trucks and airport ground support equipment in some locations. Certain states may also elect to impose restrictions apart from the revised national standards. Finally, environmental cleanup laws could require the Company to undertake or subject the Company to liability for investigation and remediation costs at certain owned or leased locations or third-party disposal locations.

Until applicability of new regulations to our specific operations is better defined and/or until pending regulations are finalized, future costs to comply with such regulations will remain uncertain but are likely to increase our operating costs over time. While we continue to monitor these developments, the precise nature of future requirements and their applicability to the Company are difficult to predict, but the financial impact to the Company and the aviation industry could be significant.

Employees

As of December 31, 2018, UAL, including its subsidiaries, had approximately 92,000 employees. Approximately 83% of the Company's employees were represented by various U.S. labor organizations.

Collective bargaining agreements between the Company and its represented employee groups are negotiated under the RLA. Such agreements typically do not contain an expiration date and instead specify an amendable date, upon which the agreement is considered "open for amendment."

The following table reflects the Company's represented employee groups, the number of employees per represented group, union representation for each of United's employee groups, and the amendable date for each employee group's collective bargaining agreement as of December 31, 2018:

(a) On October 23, 2018, United's Catering Operations employees voted to unionize under the RLA. In an election overseen by the National Mediation Board, UNITE HERE received the majority of the votes and was officially certified to represent United's frontline Catering Operations employees. The Company expects contract negotiations to begin in 2019.