Speeds above the speed of sound. The first aircraft in the world to break the sound barrier was the Bell X1. On the 14 October 1947 it reached 670mph at 42000feet (Mach 1.015). The X1 was launched by a Boeing B29 at 30000 feet, once released the rocket motor on the X1 was fired and it would begin it's ascent. Search for supersonic books on Amazon.co.uk

Speed one to five times the speed of sound

velocity greater than the speed of sound. A supersonic aircraft can fly from New York to London in less than two hours.

Is said of an airplane capable of exceeding the speed of sound, 1 160 km/h (720 mph) or so at high altitude.

having to do with velocities above the speed of sound (specifically as opposed to ultrasonic, q.v.).

(of speed) greater than the speed of sound in a given medium (especially air); "a supersonic bomber flies so fast that it must release its bombs while the target is still over the horizon"

having frequencies above those of audible sound

Operation between Mach 1 and Mach 4.

a speed in excess of the speed of sound

Faster than the speed of sound. In air, the speed of sound is about 340 m/sec (~1100 ft/sec).

Flight faster than Mach 1.