CIA's Oxcart!

[Technoid]

The story of the SR-71 right from the source: The A-12

In 1954, CIA retained the Lockheed Corporation to build the U-2 reconnaissance aircraft. Essentially a jet-powered glider, the U-2 could fly at the unprecedented height of 70,000 feet—beyond the range of Soviet fighters and missiles—and take detailed photographs of Soviet Bloc military facilities. The aircraft was ready for operations in June 1956. At the time, CIA project officers had estimated that the U-2 would be able to fly safely over the Soviet Union for two years at most before it became vulnerable to Soviet air defenses. The Soviets tracked the U‑2 from its first mission, however. The estimate had proven too optimistic, especially after initial efforts to mask the U-2’s radar image proved ineffective. A more radical solution was needed—an entirely
new aircraft.

the Skunk Works had studied various configurations called “Archangel-1,” “Archangel-2,” and so forth—a carryover from the original moniker of “Angel” given to the U-2 during its development.