All American Aviation Inc (Pittsburgh) was an airline company founded by Dr. Lytle Schooler Adams in 1937. It evolved over the decades to become US Airways, whose merger with American Airlines in 2013 created the largest airline in the world.
Dr. Adams had started experimenting with an airmail pick-up system in 1927, developing numerous patents on the system, which he rolled into All American Aviation in 1937. Initial flights of the airline pick-up service were made by a Stinson Reliant single engine high-wing monoplane. Mail containers were suspended from ropes or cables suspended from two poles. The aircraft swooped down with a suspended hook hanging below and snagged the rope or cable. This was further developed in a system that could pick up personnel.
The du Pont family brothers Richard C. du Pont and Alexis Felix du Pont, Jr. bought stock in the company in 1938—on the same date as a bill was passed in Congress to enable the U.S. Post Office to start large scale experimentation on the airmail pick-up system. Through some manipulations, the du Ponts were able to acquire majority stock and voted Richard du Pont as the new President.

Allegheny Airlines began as All American Aviation Company providing mail delivery starting on 7 March 1939. It was founded by du Pont family brothers Richard C. du Pont and Alexis Felix du Pont, Jr. In 1949 the company was renamed All American Airways as it switched from air mail to passenger service. On 1 January 1953 it was again renamed, to Allegheny Airlines.
As deregulation dawned, Allegheny, looking to shed its regional image, changed its name to USAir on October 28, 1979.