Originally Posted by WillCAD

9/11! 9/11! 9/11!

I'm going to hazard a guess that any aircraft which declares a "terror" emergency will get fighter escorts for the specific purpose of blowing it out of the sky if it turns out to have been hijacked to be used as a ballistic missile. You know, like they did on 9/11.

Who makes the decision on when to blow an aircraft full of innocent hostages out of the sky, based on what evidence that it's a threat to others, I can't imagine. But given the propensity for gross, panicked over-reaction to anything out of the ordinary (or to ordinary stuff like a forgotten camera in a seatback pocket), the mere presence of fighters would be absolutely terrifying to me if I were aboard such an aircraft.