Not quite a F/A prank, but a student prank: IPs used to get student pilots to test the pitot system by kneeling in front of the jet (T-37) and blowing on it. Of course everything tested ok and at graduation, there'd be pictures floating around of a guy on his knees with a pitot tube in his mouth.

The other one I heard was an instructor pulled the cabin heat lever in the T-37, its bleed air, and makes quite a noise in an already loud jet. The IP told my friend "**** we're going to lose the canopy. Grab it and don't let go." So my friend held on to the canopy for a few minutes before coming to his senses...