Data Watch: Top 10 U.S. Airlines, ranked by January-May 2014 Domestic Enplanements Passenger numbers in millions (000,000) Rank Carrier Jan-May 2014 Enplaned Passengers Jan-May 2013 Enplaned Passengers Pct. Change 2013-2014 1 Southwest (WN) 49.487 46.185 7.1 2 Delta (DL) 41.507 38.842 6.9 3 American (AA) 27.05 26.702 1.3 4 United (UA) 25.938 26.227 -1.1 5 US Airways (US) 20.963 20.601 1.8 Source: - ACI World Airport Traffic Report