The cockpit doors have been locked since Sept 12, 2001. It is impossible to open them from the outside without very heavy machinery that could not be operated b

The cockpit doors have been locked since Sept 12, 2001. It is impossible to open them from the outside without very heavy machinery that could not be operated by a passenger, and even then it can take over half an hour. Even if we did away with security entirely and let people carry guns on board, there would be literally zero risk of a hijacked plane in the US thanks to the locked doors. (There might be other reasons not to do that, but hijacking fears are not one of them). And even then, it's arguable that this would still be impossible. 9/11 happened because hijacking protocol never took into account the possibility that the hijackers would use the plane itself as a weapon. The people on the final hijacked plane on 9/11 did know this, because they received calls about the WTC, so they fought back and forced the plane to crash, thwarting the hijackers' plans.