The fly on the same principle as any aircraft the difference being they are propelled by jet rather than propeller.
The fly and then they shoot (:
If you mean fly on thermals like some gliders, NO.
they fly almost above 15km, where atmospheric pressure is very low.
They do make noise. If they fly very high, then you can't hear them.
over 2500 fighter jets
Some models of fighter jets have flown suborbital trajectories with apogees above 50 miles (80.47 km).
No. The fastest wind gust ever recorded in a tornado was 302 mph. By comparison, commercial jets regularly fly at 500 mph. Some fighter jets can fly at over 1,000 mph.
They fly in air. High-performance military fighter jets have engines powerful enough that they can fly straight up, like a 'rocket ship'. But aside from those, all airplanes need air in order to remain aloft.
Most fighter jets are made of aluminium, titanium and steel.
about 2,500 operational fighter jets, including those used in the fighter/bomber role.
Most military fighter jets run with a single pilot and a flight officer. The Flight Officer is not trained to fly the aircraft.
Probably not in commercial service--the FAA has mandatory retirement ages, and a Vietnam-era fighter pilot is past those. But if it's his own plane, and he's current and trained to fly jets, he could fly it.