American Airlines operates the youngest fleet among major US carriers

American Airlines has the youngest average fleet age among the three largest U.S. carriers, at 14.0 years old. Delta Air Lines and United Airlines have older fleets, with averages of 15.2 and 15.8 years, respectively. American's fleet includes a mix of older and newer aircraft, with its Boeing 777s averaging 20.5 years old and its Boeing 787s averaging around 7 years. Delta's fleet features older Boeing 767s and 757s, while United operates a mix of Boeing and Airbus aircraft. The age of an airline's fleet can impact maintenance costs and fuel efficiency. All three airlines are continually updating their fleets with newer, more fuel-efficient aircraft.