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.
PSA was one of the four airlines that formed US Airways, the others being America West Airlines, Piedmont Airlines and Allegheny Airlines. US Airways merged with American Airlines in 2014.
