As fast as it can. There are no speed limits in place for aircraft. However airlines limits speed for economic reasons. Also the way the engine is designed affects speed. The faster the engine is going, the hotter the engine will be. The turbines get the worst of this heat and if it gets to hot the turbine will fail. And the economic reason being the faster the aircraft, the more fuel you need. The Concorde was a supersonic aircraft. How ever it burned way to much fuel and that proved way to costly to operate the craft.
very fast
There is no such thing as a jet train.
400
about 40mph
250 mile
9500 mph
366mph (516kph)
depends on what jet and how fast ANSWER The Earth's circumference is about 40,000 km (kilometres). To circle it in one day you would need to travel this many km in 24 hours or 1670 km/hr in a jet, a jet boat, a very fast car or anything that will go that fast.
about 30 mph
it can go faster !
Over 400 Mph
736 mph, and the slowest can go up to 661 mph