The Bell Aircraft Company X-2 (46-674) drops away from its Boeing B-50 mothership in this photo. Lt. Col. Frank "Pete" Everest piloted 674 on its first unpowered flight on August 5 1954. Everest made the first supersonic X-2 flight in 674 on April 25, 1956, achieving a speed of Mach 1.40.

Credits - NASA