PSA Pacific Southwest McDonnell Douglas DC-9-31 N708PS CN 47068 LN 160 . Taken In January 1985 . Editorial Photo

Pacific Southwest Airlines (PSA) was a low-cost US airline headquartered in San Diego, California, that operated from 1949 to 1988. It was the first substantial scheduled discount airline. 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 yearsFor three quarters of its existence, PSA operated as a California intrastate airline. PSA's early success as an intrastate airline served as a model for Southwest Airlines, which did in Texas what PSA had done in California.[4] After the Airline Deregulation Act of 1978, PSA expanded to cities in other US western states and Mexico. PSA did not survive for long after deregulation, but its influence lives on through the continued success of Southwest.