Spy aircraft typically have the highest operational ceiling, although these values, and often the aircraft themselves, are classified.
In the early 1980s, Lockheed’s Skunk Works proposed converting the SR-71 Blackbird — the Mach 3+ reconnaissance aircraft that ...
It’s a rare opportunity indeed to take a flight to above 70,000 feet. It’s even rarer to do that in the venerable U-2 spy ...
In April 1962, Lockheed Skunk Works flew an A-12 Oxcart spy plane that required an entirely new American titanium industry ...