Havent read all the replies as of yet but has no one thought of installing Tazers or what ever the correct term may be these days, ellectronic stun guns, to the doors or other areas which could be activated by both cabin crew and pilots, COVERTLY, to down anyone attempting to enter an aircrafts off limits areas?
What a shock (sorry) a terrorist might get to find himself on the floor bound and in opperative for the duration of the flight....
There are ways to do this so come on ladies and gents think of appropriate areas (flight controls, door handles, just think of the possibilities... ) where these could be fitted and opperated from....