Quoting "Trei, Peter" :

What would actually happen is that there would not be an attempt to hijack the plane. The only reason the terrorists pulled it off on the first three was that the usual protocol for hijacks involves landing, and letting most/all of the passengers off unharmed. For disarmed passengers, the best option for survival was to anticipate this protocol, and sit tight.

What would actually happen is that in order to commit an act of suicidal terrorism all you'd have to do is stand up and rely on the other passengers to shoot up the plane for you. It's a great stratagy, requires almost no effort and no weapons. I everyone in the Us had that kind of attitude and a handgun how many innocents would hav been killed for looking suspicious so far? -- If you can read this you`ve gone to far