American Vs Delta Vs United: Which Major US Carrier Has The Oldest Fleet?

By some measures, including fleet size, American Airlines, Delta Air Lines, and United Airlines are the three largest airlines in the world. When it comes to mainline fleet size, all are similar, with around 1,000 aircraft in service. They also operate almost all the long-haul international flights served by US carriers, although JetBlue does operate some transatlantic flights with Airbus A321s, and Hawaiian operates some international flights in the Pacific region.