One thing going unanswered - is a gun really the best solution for a terrorist on an airplane? My question about structural damage was answered, seems like a low risk. But what about the risk of...missing, in an area where there are plenty of people, all within the same plane (of view), who stand a pretty good chance of eating that bullet?
I've met very few people who can shoot with the kind of accuracy that might be necessary, particularly when under stress, particularly in unsettled situations, etc., etc. I'm not exactly sure your a CCW-holder, regardless of how well he punches holes in paper pictures of OBL, is going to be able to hit what he means to, particularly when you look at the windshield of the cars that were sitting still during traffic stops and realize that those bullets came from people who have to meet certain standards as a part of their jobs.
I know, I know, the response is "well, how do you know your average CCW-holder doesn't practice more than those yokel police officers." Shooting at people ain't shooting at paper targets, no matter what kind of practice you do for it. I'm just not particularly confident that your average...anyone...would be able to get it done, and I'm not particularly hopeful for people in the line of sight or out of it by a considerable margin.
In other words, I frankly don't like the idea that some guy with a gun might shoot me accidentally (though out of the very best of intentions) when I'm sitting next to a guy intent on hijacking the plane, when I could just punch him in the jimmy and he's got no significant weapons because no one can get on the plane with a gun or knife. Sometimes the cure can be worse than the problem.
Which is why I asked the question about why a taser is not an option. Is there some reason that tasers are practical for ordinary law enforcement use, but not on an airplane?