Most everyone older than fifty remembers the U-2 spy plane and its successor, the SR-71 Blackbird. But few (including me) are aware of another plane that bridged the gap between these two Cold War airplanes: The A-12 “Oxcart.”
Like the U-2, the A-12 was a tool of the CIA, used to conduct high-altitude reconnaissance flights over hostile territory. The plane could reach altitudes in excess of 90,000 feet, and speeds greater than Mach 3. Each of the two turbojet engines produced more horsepower than all four of the turbines on the Queen Mary ocean liner. (Of course, it took a lot fuel to churn out that kind of power — 11,000 pounds per hour).
The A-12 flew only a few missions, first over Cuba, then in Southeast Asia during the Vietnam War, before being replaced by the Air Force SR-71. The SR-71 was based on the A-12, so it looks very similar, but there were significant design and performance differences.
The SR-71 was retired in 1991. (You can actually see and touch a retired SR-71 on display at the Kansas Cosmosphere in Hutchinson.) Much of the reconnaissance data collected by these planes can now be gathered much cheaper and faster by satellites. Still, the quiet manner in which the SR-71 was retired leads one to wonder if the government has replaced these old warbirds with something even more exotic.