All your points, Steepclimb, appear (to this layperson) well worth taking into account, even beyond the fact that an airliner brought a very long distance would now have little fuel left so it would be a much less effective weapon - unless it were transporting fuel in the first place in which case it would have plenty remaining, its entire cargo.
But although I am not a pilot and have no expertise whatsoever in counterterrorism, may I speculate, as I have done on another thread,
http://www.pprune.org/forums/showthr...0&pagenumber=5 ,
that the terrorists might, in the near term or longer term, use an aircraft not as a fuel bomb or brute force impact vehicle but rather, as a means to transport a nuclear device. In that case the parameters could be quite different.
Evidently the intelligence services don't think Osama & Co. have current access to any nuclear weapons. But shouldn't this potential threat become part of the broad public discussion starting now? Shouldn't we begin to think about how to counter this over the long term? If the WTC/Pentagon attacks were "unthinkable", can you imagine something 300 times worse, such as a 5xHiroshima-class device over Wall Street or Times Square? Shouldn't we be devoting 80% of our anti-terrorism resources to this (and other nuclear scenarios)? Aren't the rest - even the radiological "dirty bomb" - microscopic by comparison?
It worries me that no one appears to be considering the hijack threat in this nuclear context. If I'm speaking out of place, or if I am being too alarmist, anyone is welcome to let me know.