Open the canopy on a jet at mach one. :-/
Do the real jets allow you to open in flight? I would assume it'll be ripped off from the hinges, smashing the tail plane.
The same for under carriage, I can alow gear at high speeds, wouldn't it be damaged?
Lowering the gear while at cruise speeds would not damage the gear , It would completely destroy them!

In the case of military jets the cockpits have to be able to open for ejection purposes and most of them blow off so they do not hit the tail of the aircraft. 8-)