Unfortunately all the points you raise are easily countered by a determined, somewhat aeronautically savvy terrorist.
Bull biscuits! How?
And Silverhawk, is that a bit of racism I smell under your breath?
Some people like the idea of perpetual war whilst others look for solutions to end this madness. Let's stop conjuring up these dangerous thoughts. As someone has already pointed out. Life is very fragile, it can take the smallest of violent acts to disrupt a peaceful life.....but what's new? these things have been happening since time began.
The best way to avoid such a tragedy would be to get our moral backsides into gear and deal with the core issues that might be the cause of such a thing. Just my tupence.