Actually, PSA was merged into USAir shortly after Air Cal was merged into American. The Air Cal/American merger occurred in 1987 and PSA was integrated into USAir in April of 1988.
Shortly after both mergers, American began to replace former Air Cal routes with American Eagle Convair 580's on routings such as OAK
Needless to say, the service didn't last long.
Shortly after AA
pulled out of several intra-California routes, Southwest embarked on a major expansion. They came into OAK
for the first time, having served SFO
in the Bay Area since 1982. USAir, with its higher cost structure, couldn't compete with Southwest in intra-California flying. Southwest's OAK
operations were (much like PHL
) almost an immediate success and frequencies were quickly increased. Within a very short time, Southwest had entered the OAK
, and OAK
market with multiple frequencies.
USAir meanwhile, was still trying to digest Piedmont which was merged into USAir in August 1989. Losses began to quickly mount and the the gulf war broke out in early 1991. USAir had a very hodge podge fleet of 727's, 737-200/300/400's, Fokker F-28's, MD
-80's, BAe-146's. In the Spring of 1991, as losses continued to mount, USAir grounded the BAe-146 fleet (inherited from PSA) and closed most of the satellite airports in California including OAK
as well as the smaller stations in the Pacific Northwest. It was quite a blow to the good folks of PSA.
USAir pretty much packed its bags and ran back east seeking refuge in safer territory (with its high cost, high fare model) hoping to never have to compete with the likes of Southwest. And you know the rest of the story...
United's B747-400. "She's a a cruel lover."