In early 1981 United Airlines announced it would inaugurate separate nonstop service on June 12, 1981 on the Denver to Houston, San Francisco to Houston, Denver to Phoenix, San Francisco to Phoenix and Denver to Tucson routes, utilizing Boeing 727 aircraft.

This cover was carried on the June 12, 1981 inaugural United Airlines flight from the San Francisco, California Airport Mail Facility to Houston, Texas (where it was backstamped) and is listed in The American Air Mail Catalogue as UA-D127SEf.