Designed as a B-52 replacement, The North American Aviation XB-70 Valkyrie is the prototype of the B-70 nuclear-armed, deep-penetration strategic bomber for the U.S. Air Force’s Strategic Air Command. North American Aviation designed the Valkyrie bomber as a large, six-engined aircraft capable of reaching Mach 3 while flying at 70,000 feet (21,000 m).

Only two prototypes of the North American XB-70 Valkyrie were constructed before project cancellation.