Flight airspeed record
Determining the fastest aircraft in the world is difficult, because of the wide variety of designs. For example, most high-speed aircraft are unable to take off under their own power, requiring a carrier aircraft.
The Space Shuttle is the fastest aircraft, reaching speeds of 17,500 miles per hour. During reentry when it flies at its highest speed it is a glider, relying on residual speed from being in orbit. It is unable to take off under its own power, requiring two solid rocket boosters and a discardable fuel tank to reach orbit. During ascent the airspeed is under Mach 2 whilst in what would normally be considered to be the atmosphere; the Shuttle leaves the atmosphere as soon as possible, and fairly plausibly isn't an aircraft as most people would consider the term on the way to orbit.
The Boeing X-43A is the fastest air-breathing aircraft, having set a speed record of 11,200 km/h (7,000 mph), or Mach 9.68, on November 16, 2004. However, it is unmanned, and relies on a carrier aircraft to reach altitude, and a discardable booster rocket to reach the operating speed of its scramjet engine. It is also incapable of landing.
The rocket-powered X-15 was the fastest powered, manned aircraft, reaching a top speed of 7,274 km/h (4,510 mph) on October 3, 1967. However, it was rocket-powered, carrying both fuel and oxidizer. It requires a carrier aircraft to take off.
The SR-71 "Blackbird" is usually considered to have been the fastest "regular" aircraft, with a sustained top speed of 3,529.56 km/h (2,188 mph). It was a manned aircraft powered by air-breathing engines, and was capable of taking off and landing unassisted on conventional runways.