[White Owl]

In real life I made my living as a general aviation A&P mechanic for several years, and also used to fly small aircraft occasionally. The only times I've ever seen chocks intentionally left blocking the aircraft's wheels during engine start and run-up were when testing the engine(s) for maintenance work. If the pilot expects to actually go anywhere, he removes the chocks before engine start. Brakes are perfectly suitable for holding the aircraft in one place, even at full throttle.

That's for small civil aircraft anyway. Military may do things differently.