The SR-71 Blackbird was a spy plane built by the U.S. in the 1960s, and it remains the fastest jet-powered aircraft ever flown. It reached 2,193 miles per hour, or about three times the speed of sound. At that speed, a missile fired at the plane could be outrun simply by pushing the throttle forward.
Flying that fast turned the plane into a small oven. The air rubbing against the body heated parts of it to over 500°F. To survive, almost the whole plane was built from titanium, a tough silvery metal that doesn’t melt easily. The plane actually grew several inches longer in flight as the metal expanded from the heat.
The Blackbird was so unique that its fuel tanks leaked on the ground. They were built loose so the metal could expand in the air without cracking. So pilots would take off with leaking fuel, then refuel from a tanker plane once they were already up high and the metal had stretched and sealed itself shut.
