The security theater that has been implemented since 2001 has raised the cost (in dollars, time and convenience) of air travel enough to divert enough travelers to the nations highways that I posit that we as a nation have suffered more death and injury than had we reacted to the Sep 11 attacks by literally doing nothing at all.
We kill more people on the roads annually than more than 15 such attacks would have done.
Meanwhile, UBL's grand master plan stopped working even before the last airplane was grounded that day - the passengers found out that the rules (give hijackers what they want and you get out alive) had changed and the last plane did not make its target. And because everybody knows the new rules of engagement, that plan will never work again - regardless of any changes (or lack thereof) in government policy.
There are exactly 3 things necessary for airport security:
1. Make sure that no luggage gets on the plane without its associated passenger (you can't blow up the plane without going along for the ride).
2. Metal detectors to keep guns out. The alternative is allowing anybody to carry, thus insuring the entire plane will wind up swiss cheese if any funny business starts. That's a less than positive outcome, IMHO.
3. Lock and bar the cockpit doors for the flight's duration.
And for extra credit
4. Research applying the military's UAV technology to the air transport system. If enough improvements can be made in assuring positive aircraft control, there's no reason the flight deck as we know it needs to exist on the plane at all.