Found and Explained Official on MSN

The CIA’s Mach 3 spy drone that went horribly wrong

After the U-2 shootdown, the CIA pursued an unmanned reconnaissance drone faster than any fighter. The Lockheed D-21 was launched from modified aircraft and powered by a ramjet, reaching Mach 3 speeds ...
Found and Explained Official on MSN

XB-70 Valkyrie: The Mach 3 bomber ahead of its time

Designed to fly above 70,000 feet at three times the speed of sound, the XB-70 Valkyrie was meant to be the ultimate ...