Its just attitude and knowledge that picks the winner in that scenario of 9 /11.One group of people on one of the planes bowed up and decided to fight.Yeah they died but so did the people on the other planes.At least they fought and died saving other lives on the ground!
The other planes were overtook and destroyed with many civilian casualities!
The difference I think was reaction time and attitude!
My understanding is that the difference was that someone on the plane had a cell phone, and heard from his wife that the hijackers were crashing the planes. Armed with this knowledge, the passengers knew they had nothing to lose, and everything to gain.
Airport security is all well and good, but the cause of 9/11 was not a physical security failure, it was an intelligence failure. All the hype about metal detectors and trained security personnel is just smoke to make us look the other way.