After reading readers letters in a recent Flight magazine and posts on here I'm gobsmacked that nobody seems to picked up the bleedin' obvious about NOT reinforcing cockpit doors. THE HIJACKERS WERE TRAINED AS PILOTS!! What price a reinforced door you cannot access when the PA announces that those at the helm are on a suicide mission and there is NO access to the cockpit then!!
Impossible for this to happen....just look at the well advertised First Officer programmes in the US where low hour pilots can buy the right hand seat on major carriers (albeit mainly cargo) Let's hope the US have plugged THAT loophole