Largest US Airlines by Fleet Size and Revenue
American Airlines is the biggest airline in the United States by fleet size and passenger volume, operating more than 900 aircraft across mainline and regional operations as of the most recent public filings, with 2024 revenue reaching roughly 58 billion dollars, according to the company's latest annual report and industry data from Forbes.
Delta Air Lines ranks second in fleet size and revenue, with a mainline fleet of roughly 900 aircraft and total operating revenue close to 54 billion dollars in 2024, supported by a strong international network and cargo operations, as reported in the company's financial disclosures and airline industry analyses.
Passenger Volume and Route Networks
Southwest Airlines carries the most domestic passengers among low-cost carriers, operating a fleet of more than 800 aircraft and serving a dense network of short-haul routes, while United Airlines focuses on a global hub-and-spoke model with a mainline fleet of roughly 950 aircraft and extensive international long-haul service.
Alaska Airlines, following its merger with Horizon Air and regional partners, operates a combined regional and mainline fleet of more than 500 aircraft, emphasizing routes along the West Coast and expanding into new markets through codeshare and joint venture agreements with partners such as SEC filings and industry reports.
Revenue Models and Fleet Composition
The largest US carriers rely on a mix of passenger fares, cargo revenue, and ancillary fees, with mainline fleets dominated by narrowbody aircraft such as the Boeing 737 family and Airbus A320 family, while widebody planes like the Boeing 777 and 787 support long-haul international routes.
Regional operations are handled by contracted carriers using smaller jets and turboprops, allowing the major airlines to extend their networks without expanding their own mainline fleets, a structure documented in airline financial reports and carrier partnership announcements shared with investors and regulators.