The design was largely obsolete by the time it was completed due to the rapidly increasing performance of contemporary jet engines, and only two prototypes were built.

Another design change was the ability to vary the angle of incidence of the wing as a whole, tilting it up for low speed operations during takeoff and landing, and then "leveling it off" for high-speed flight and cruise.

By the time fire apparatus arrived, driving seven miles (11 km) across the dry lake bed, the tail section had been reduced to ashes.

The United States Air Force decided to wait the short time needed to introduce newer and much more capable designs created as a part of the 1954 interceptor project.

The Thunderceptor, like the other interceptor designs of the era, had extremely short flight times on the order of 25 minutes, making them almost useless for protecting an area as large as the United States.

The 1954 designs outperformed the XF-91 in speed, range, and loiter time, as well as including the radar and fire-control systems needed for night and all-weather operation.

The surviving prototype, 46–0680, is exhibited in the Research & Development Gallery at the National Museum of the United States Air Force at Wright-Patterson AFB in Dayton, Ohio.

[3][4] Data from The Complete Book of Fighters,[5] Air Force Legends #210 : Republic XF-91 Thunderceptor[6]General characteristics Performance Armament