Paying for some F-16s on standby at certain points around the country seems reasonable to me. I mean, the TSA costs us ~7 billion a year anyways.

I agree, but if some people are going to cause a disproportionate need for them, then those people should pay for it more than the rest.

Really, though, that was more of a glib remark. The more salient point IMO is the fact that the military is far from guaranteed to succeed in bringing down a hijacked airliner before it hits its target, or without killing other people on the ground.

Unless you don't live in USA or you don't pay your taxes, you already pay for it -- a.k.a Norad.

Besides, since 911 the doors of plane cockpits are almost like a bank vault.

Yes, even to the point of locking out the co-pilot for a suicide mission.

:(

Europe didn't (doesn't?) have the 2 person rule like the US does.

This already happens. WADS, EADS, etc.