That, and the knowledge that hijackers are going to kill you, so you need to fight back. 9/11 only worked because the passengers on three of the planes "knew" t

That, and the knowledge that hijackers are going to kill you, so you need to fight back. 9/11 only worked because the passengers on three of the planes "knew" that being compliant was their best chance of survival in a hijacking. When passengers on the fourth plane discovered this was no longer the case, they foiled the attack.