[Cushman]

What makes an airplane with 100 people on it more "big a deal" than a bus with the same?

The effort spent on security is wildly disproportionate to the risk-- based, it seems, on the supposition that terrorists care fabulously more about damaging faith in American air travel than actually killing Americans.

I'm not saying I know anything one way or another, but that seems crazy.

[MSexton]

An airplane can easily go off course and (busses don't work too well off road), and hit anything, taking down large buildings and downtown areas. A bus could easily kill the 100 passengers and some nearby cars.

[ams6110]

I recall a U-haul taking out a Federal building some year back.