1970s: Deregulation and rebranding
Allegheny changed its name to USAir in 1979 following the passage of the Airline Deregulation Act the previous year, which enabled the airline to expand its route network into the southeastern United States.
USAir was a launch customer for the Boeing 737-300, as the airline needed an aircraft with greater capacity to serve its rapidly growing Florida markets. USAir was the world's largest operator of DC-9 aircraft at the time and approached McDonnell Douglas to negotiate a new airplane design. However, in the late 1970s, the McDonnell Douglas' proposed successor to the DC-9-50 did not suit USAir's requirements. After the negotiations with McDonnell Douglas broke down, Boeing came forward with a proposed variant of the 737. USAir selected the new 737 aircraft, and the company worked closely with Boeing during its development, taking delivery of the first plane on November 28, 1984.
1980s: Mergers and expansion
Source:Air Transport World
USAir expanded in the late 80s purchasing San Diego-based Pacific Southwest Airlines (PSA) in 1986 and Winston-Salem, North Carolina-based Piedmont Airlines in 1987. The PSA and Piedmont acquisitions were completed in 1988, and 1989, respectively.
The PSA acquisition gave USAir its first routes on the West Coast, while the Piedmont acquisition gave USAir a strong east-coast presence and hubs in Baltimore and Charlotte, which remained key hubs for USAir in later years. The Piedmont acquisition in 1989 was the largest airline merger until then, and USAir became one of the world's largest airlines, operating more than 5,000 flights daily. Following the acquisitions, USAir closed down PSA's hubs in California and Piedmont's hubs in Dayton and Syracuse.
Crystal Park Four, former headquarters in Crystal City, Arlington County.
By 1990 the airline had consolidated its headquarters, moving from Washington National Airport to a new building at Crystal City in Arlington County, Virginia, near the airport. Maintenance and operations headquarters stayed at Pittsburgh International Airport.