Despite its technical triumphs and support from aviators, the XB-70’s operational future unraveled almost as quickly as it took flight. The North American XB-70 Valkyrie emerged from a United ...

The XB-70 Valkyrie, a Mach 3-capable bomber developed during the Cold War, was designed to outpace Soviet air defenses. Powered by six turbojet engines, it could reach 2,076 mph at 73,000 feet.