DO PLANES HAVE A SPEED LIMIT ON THE GROUND OR IN THE AIR?
M. AND M. JOYCE, MOORE CREEK
In the air, the answer is no and yes.
A modern aircraft such as the Airbus A380 flies at a cruising speed of about 900 km/h. Its actual speed over the ground can vary quite a lot depending on whether the aircraft is travelling with a tailwind or against one. Travelling from west to east, due to prevailing winds, an aircraft will generally travel at a higher speed over the ground, occasionally reaching close to 1000 km/h.
However, it is possible for commercial aircraft to fly much faster than that.
Flying at an altitude of 60,000 feet, the delta-wing Concorde achieved speeds of mach 2.04, almost 2500 km/h. If Concorde was still operating and flying from Melbourne and Sydney to London, the flight time would be under 12 hours, even allowing for two refuelling stops.
Although it was quick, Concorde was uneconomic to operate. It was also bedevilled by another factor that limits aircraft speed over populated areas, the sound barrier. When an aircraft exceeds 1236 km/h, it "breaks" the sound barrier and creates a sonic boom that sets dogs howling and annoys folks below. If you've experienced a sonic boom at a military air show it's not something you'll forget in a hurry. For that reason it is not possible to operate commercial aircraft at supersonic speeds except over the oceans, which is precisely the routes that Concorde flew.
When they taxi between gate and runways, commercial aircraft are restricted to a maximum speed of 20 knots, or 37 km/h, and 15-22 km/h on turns.