A lot. A LOT of money.
It is the Lockheed SR-71 "Blackbird", a reconnaissance aircraft.
Black
3.5
2193 mph
Stratosphere
2200 mph
If you are refering to the SR71 blackbird, the military plane, it was designed and built by Lockheed Martin. The SR-71 Blackbird was built by the famous Lockhead "Shunk Works" Heading up the team was Clarence L. "Kelly" Johnson one of aviation's most important aircraft designers.
The SR-71 Blackbird was introduced into service in 1966.
No it just flew very high to avoid radar.
About 3 times the speed of sound. (3 mach)
No it is an advanced, long range, Mach 3+ strategic reconnaissance aircraft.
The maximum speed of a SR71 is 2,200 mph at 80,000 ft.