As a First Lieutenant and later Captain, he was assigned to inspect Hispano-Suiza aircraft engines manufactured under French license at the Wright-Martin plant in New Brunswick, New Jersey.

Rentschler left the Army convinced that future aircraft would require lighter-weight engines with much greater power and higher reliability.

On July 23, 1925, they agreed to fund its development, creating the Pratt & Whitney Aircraft Company in which Rentschler and Mead had a controlling position.

[3] Pratt & Whitney Aircraft's first engine, completed on Christmas Eve 1925, was named the Wasp by Faye Belden Rentschler, whom Frederick had married July 25, 1921.

The 425 horsepower (317 kW) Wasp easily passed its official qualification test in March 1926 and the Navy ordered 200 engines.

[2] In 1934, UATC was broken up, and its manufacturing interests east of the Mississippi River became United Aircraft Corporation, headquartered in Hartford with Rentschler as president.

[7] Pratt & Whitney's former company airfield, located in East Hartford, Connecticut, was named Rentschler Field in his honor.