After the war, he was assigned to flight-test duty at Wilbur Wright Field near Dayton, Ohio. There he impressed and befriended Chuck Yeager. When Yeager was later asked whom he wanted for flight crew for the supersonic Bell X-1 flight, the first flight to break the sound barrier, he named Hoover. Hoover became Yeager's backup pilot in the Bell X-1 program and flew chase for Yeager in a Lockheed P-80 Shooting Star during the Mach 1 flight. He also flew chase for the 50th anniversary of the Mach 1 flight in a General Dynamics F-16 Fighting Falcon.