Southwest has operated 727s on two seperate occasions. From March-December 1979, they wet-leased a 727 from Braniff for higher capacity services DAL-HOU and HOU-MSY in the immediate post-deregulation expansion. That aircraft was N406BN.

Subsequently, in 1983 when Boeing's 737-300 program was running behind schedule, Southwest leased N551PE, N561PE, N563PE, N564PE, N566PE and N569PE from PeoplExpress to expand operations to the West Coast. Those leases were terminated with arrival of the 733s in 1985.