Southwest Airlines Co. operates as a passenger airline company that provides scheduled air transportation services in the United States and near-international markets. As of December 31, 2023, the company operated a total fleet of 817 Boeing 737 aircraft; and served 121 destinations in 42 states, the District of Columbia, and the Commonwealth of Puerto Rico, as well as ten near-international countries, including Mexico, Jamaica, the Bahamas, Aruba, the Dominican Republic, Costa Rica, Belize, Cuba, the Cayman Islands, and Turks and Caicos. It also provides inflight entertainment and connectivity services on Wi-Fi enabled aircraft; and Rapid Rewards loyalty program that enables program members to earn points for dollars spent on Southwest base fares. In addition, the company offers a suite of digital platforms to support customers' travel needs, including websites and apps; and SWABIZ, an online booking tool. Further, it provides ancillary services, such as Southwest's EarlyBird Check-In, upgraded boarding, and transportation of pets and unaccompanied minors. Southwest Airlines Co. was incorporated in 1967 and is headquartered in Dallas, Texas.

American Airlines Group Inc., through its subsidiaries, operates as a network air carrier. The company provides scheduled air transportation services for passengers and cargo through its hubs in Charlotte, Chicago, Dallas/Fort Worth, Los Angeles, Miami, New York, Philadelphia, Phoenix, and Washington, D.C., as well as through partner gateways in London, Doha, Madrid, Seattle/Tacoma, Sydney, and Tokyo. It operates a mainline fleet of 965 aircraft. The company was formerly known as AMR Corporation and changed its name to American Airlines Group Inc. in December 2013. American Airlines Group Inc. was founded in 1926 and is headquartered in Fort Worth, Texas.

Alaska Air Group, Inc., through its subsidiaries, operates airlines. It operates through three segments: Mainline, Regional, and Horizon. The company offers scheduled air transportation services on Boeing jet aircraft for passengers and cargo in the United States, and in parts of Canada, Mexico, Costa Rica, Belize, Guatemala, and the Bahamas; and for passengers across a shorter distance network within the United States, Canada, and Mexico. Alaska Air Group, Inc. was founded in 1932 and is based in Seattle, Washington.

Frontier Group Holdings, Inc., provides low-fare passenger airline services to leisure travelers in the United States and Latin America. The company sells its products through direct distribution channels, including its website, mobile app, and contact centers. As of December 31, 2023, it had a fleet of 136 Airbus single-aisle aircrafts. Frontier Group Holdings, Inc. was founded in 1994 and is headquartered in Denver, Colorado.

Sun Country Airlines Holdings, Inc., an air carrier company, operates scheduled passenger, air cargo, charter air transportation, and related services in the United States, Latin America, and internationally. It operates through two segments, Passenger and Cargo. The company also provides crew, maintenance, and insurance services through ad hoc, repeat, short-term, and long-term service contracts; and loyalty program rewards. As of December 31, 2023, its fleet consisted of 60 Boeing 737-NG aircraft, which includes 42 passenger fleet, 12 cargo, and 6 leased to unaffiliated airlines aircraft. The company serves leisure, and visiting friends and relatives passengers; charter and cargo customers; military branches; collegiate and professional sports teams; wholesale tour operators; schools; companies; and other individual entities through its website, call center, and travel agents. Sun Country Airlines Holdings, Inc. was founded in 1983 and is headquartered in Minneapolis, Minnesota.

Mesa Air Group, Inc. operates as the holding company for Mesa Airlines, Inc. that provides regional air carrier scheduled passenger services. The company offers scheduled flight and cargo services. As of September 30, 2023, it operated a fleet of 80 aircraft with approximately 296 daily departures to 86 cities in the United States and Mexico. Mesa Air Group, Inc. was founded in 1982 and is headquartered in Phoenix, Arizona.