The Lockheed YF-12
was a prototype interceptor Mach 3 +, based on project SR-71. Only three were built and only one remains today. The YF-12A program was canceled at the end of 60 due to financial reasons.
Top speed: 2,275 mph
Range: 2,983 mi
First flight: August 7, 1963
Number built: 3
Unit cost: 15,000,000–18,000,000 USD (1963)
Developed from: Lockheed A-12