Pacific Southwest Airlines (
PSA) was a United States
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 40 years."