Two things are stopping another 9/11: cockpit doors and passengers knowing they have nothing to lose. Before 9/11, hijackings were pretty survivable events, bu

Two things are stopping another 9/11: cockpit doors and passengers knowing they have nothing to lose. Before 9/11, hijackings were pretty survivable events, but your best bet for survival was to cooperate and wait it out. The 9/11 hijackers cashed in that history all at once. Now people know their best chance of survival is to fight back as hard as they can.