Another idea for preventing hijackings, without the added cost of
Israeli-style armed air marshals:
letting armed police fly for free. It could work, you know; if
there is an armed out-of-uniform cop on the plane, a hijacking is much more likely to fail; if there might be (and who's to say there isn't?), the odds of success may be sufficiently reduced to make suicide attacks less desirable.
(Do you still get the 72 virgins in the afterlife if you're gunned down harmlessly in the aisle, and if that was the most likely outcome?)
Though armed air marshals (or at least flight staff trained in hand-to-hand
combat) could still be a good idea.