aeroplane

Ok, I'll not tell you, but they use the tractor... for short pushbacks and tight turns.

No, they dont use the jet engine at part of the time. They use it all the time.

The jet engines are the only power source for aircraft moving. What happens is that as the airplanes are large and the engines have high inertia and responds slowly to the commands when in iddle, they give it just a little throttle during a short period at a time, to allow the aircraft to start moving slowly, and then controlling it through the brakes and making turns with a handwheel, located usually in the left side of left seat. In low speeds, this wheel gives a good amount of steering in the wheel landing gear. At higher speeds (during run to takeoff), this wheel is suppressed and the commands to the steering wheels are done in conjunction with the rudder through the peddals, in a much narrower range.

And... sometimes... due to the cost of that guy with the tractor in some airports, I've seen some companies making a jet engined pushback (using the reverse...)