That, and there's one more benefit. Before 9/11 we were taught to deal with hijackers by letting them get what they want, because up until that point they usual

That, and there's one more benefit. Before 9/11 we were taught to deal with hijackers by letting them get what they want, because up until that point they usually freed their passengers at that point. Now, passengers have nothing to lose by fighting back, so the response is "do anything you have to to end the threat".