The military says Mach 3 (three times the speed of sound) but it can go way faster.
very fast
There is no such thing as a jet train.
most military air combat jet aircraft can go over mach 1.0, passenger aircraft fly at around mach 0.80
400
about 40mph
It depends on the jet or aircraft you are refering too some go into our atmosphere
250 mile
366mph (516kph)
9500 mph
Go over MACH 1. Preferably in a military jet.
it can go faster !