| name | Hub | image | date Ceased operations | date Commenced operations | IATA Code | ICAO Code | city Headquarters | administrative division Headquarters | country Headquarters | continent Headquarters | Country | continent | Parent | number of aircrafts | number of destinations | Website |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AirTran Airways | Baltimore–Washington International Airport |  | 28/12/2014 | 26/10/1993 | FL | TRS | Dallas | Texas | United States | Americas | United States | Americas | Southwest airlines | 140 | 69 | Website |
| ATA Airlines | Midway International Airport |  | 03/04/2008 | 1973 | TZ | AMT | Indianapolis | Indiana | United States | Americas | United States | Americas | Southwest airlines | 29 | 13 | Website |
| Morris Air | Salt Lake City International Airport |  | 1994 | 1984 | KN | MSS | Salt Lake City | Utah | United States | Americas | United States | Americas | Southwest airlines | 21 | 21 | Website |