Airline Accountability Index
How US carriers' filed delay minutes were coded, May 2026
75.2% of reported delay minutes were coded as carrier delay or late-arriving aircraft. 4.1% were coded as extreme weather.
7 reporting carriers · 442,954 domestic flights
Southwest Airlines81.2% carrier + late aircraft · 120,646 flights
Frontier Airlines75.9% carrier + late aircraft · 18,423 flights
American Airlines79.1% carrier + late aircraft · 88,740 flights
United Airlines62% carrier + late aircraft · 74,200 flights
JetBlue Airways69.2% carrier + late aircraft · 19,806 flights
Delta Air Lines73.7% carrier + late aircraft · 91,955 flights
Alaska Airlines70.5% carrier + late aircraft · 29,184 flights
- Carrier delay
- Late-arriving aircraft
- Air traffic system
- Extreme weather
Monthly aggregate filing codes. They cannot establish what caused any individual flight.