PSA Pacific Southwest Airlines McDonnell Douglas DC-9-31 N706PS CN 47020 LN 126 . Editorial Image

Pacific Southwest Airlines (PSA) was a regional U.S. airline headquartered in San Diego, California, that operated from 1949 to 1988. It was the first large discount airline in the United States. PSA called itself "The World's Friendliest Airline" and painted a smile on the nose of its airplanes, the PSA Grinningbirds. Opinion L.A. of the Los Angeles Times called PSA "practically the unofficial flag carrier airline of California for almost forty years.The airline initially operated as an intrastate airline wholly within the state of California. This strategy which avoided the steep costs from federal regulation would later serve as the model for Southwest Airlines, doing in Texas what PSA had done in California.[3] After the Airline Deregulation Act of 1978, PSA expanded to cities in other western states, and eventually to several cities in Mexico