Lockheed Martin SR-72 Son of Blackbird

The Lockheed Martin SR-72, colloquially referred to as “Son of Blackbird”, is an American hypersonic UAV concept intended for intelligence, surveillance and reconnaissance (ISR) proposed privately in 2013 by Lockheed Martin as a successor to the retired Lockheed SR-71 Blackbird. The company expected an SR-72 test vehicle could fly by 2025.
Unconfirmed reports about the SR-72 date back to 2007, when various sources disclosed that Lockheed Martin was developing an airplane able to fly six times the speed of sound or Mach 6 (4000 mph; 6400 kmh; 3500 kn) for the United States Air Force.