Southwest Airlines began revenue service on June 18, 1971, as an intra-Texas carrier molded in the image of California’s Pacific Southwest Airways (PSA). The initial service was from Dallas to San Antonio. The Texas Aeronautics Commission had approved Southwest’s application on February 20, 1968, but objections from Braniff, Continental and Trans Texas, along with court actions, delayed the initial service until 1971. Dallas to Houston service quickly followed the Dallas to San Antonio route. In November 1991, with a bold move against the conventional wisdom of the time, Southwest moved one half of its Houston operations from the Houston Intercontinental Airport to Hobby field which was much closer to downtown Houston. The amount of traffic on the route increased so dramatically that by May 1992 all of the Houston service operated from Hobby. Southwest also operates its Dallas service from Love Field instead of the newer D/FW International Airport.

Southwest originally operated three Boeing 737-200 aircraft built for Aloha, Air California and PSA. Southwest used Boeing 727 aircraft leased from Braniff and People Express. These aircraft were later replaced by Boeing 737-300s. Southwest continued to use only 737s.

On April 7, 1996 Southwest Airlines inaugurated service to Orlando.

No cachets were provided for the inaugural mail.

This cover was one of the few pieces of mail carried on the inaugural Southwest Airlines flight from New Orleans, Louisiana to Orlando, Florida and is listed in The American Air Mail Catalogue as WN-D55Ef.