The Lockheed SR-71 Blackbird is the fastest air-breathing manned aircraft ever built, capable of sustained flight above Mach 3 (over 3,500 km/h). Developed by Lockheed's Skunk Works, it set Cold War speed records that still stand, and even survived dramatic close calls during reconnaissance missions.

Germany's Messerschmitt Me 262 was the world's first operational jet fighter, entering combat in 1944 during World War II. Its turbojet engines made it markedly faster than the piston-engined fighters of the era, helping usher in the jet age of military aviation.

Most modern fighter jets can exceed twice the speed of sound (Mach 2, around 2,400 km/h). Specialised aircraft fly faster still — the SR-71 reconnaissance jet topped Mach 3. Sustained high speed generates intense heat and places heavy stress on both the airframe and the pilot.

Mach number expresses speed relative to the speed of sound: Mach 1 is the speed of sound (about 1,235 km/h at sea level), Mach 2 is twice that, and so on. Fighter jets are often described by their top Mach number, a key measure of performance.

Most modern military jets are painted in shades of grey because it makes them harder to see against the sky and at distance, improving stealth and survivability. Earlier camouflage schemes used greens and browns better suited to low-level flying over land.