| airline (21) | revenue (6) | change (10) | aircraft (13) | company (9) |
| lowcost (21) | spirit (13) | people (7) | legacy (7) | demand (8) |
| southwest (11) | flying (6) | flights (15) | essentially (7) | airlines (16) |
| business (16) | through (8) | operating (8) | carrier (7) | routes (8) |
| between (9) | leisure (7) | passenger (6) | carriers (17) | operate (7) |