The problem (as I'm sure many others have stated before) is that airport security doesn't really solve the problem of being able to crash a plane into a skyscraper. However, reinforced cockpit doors, armed pilots, and a belief that a hijacker will use a plane to commit suicide instead of as hostage do effectively solve this problem.

Thats how I see it. Also if the goverment crebily commits to a 'we will shut you down policy'.

Of course in the contract you have to agree that its ok with you that if the plane does get hijacked its ok with you to shut it down.