Over three decades United, Delta and American have clustered near a fifth of capacity each, with Southwest's long climb behind them.
What this shows: The chart covers 1995 to 2024. It plots American, Delta, United, Southwest, JetBlue, Alaska, Spirit and Frontier on a vertical axis of Share of available seat-miles (%). Latest values: American 19.4; Delta 20.1; United 21.7; Southwest 13.2; JetBlue 4.9; Alaska 4.7; Spirit 3.9; Frontier 3. Data run through 2024.