Directed by whom? There is no conceivable threat that would make a pilot agree to fly their plane into a building, and reinforced cockpit doors make it implausible to enter the cockpit without damaging the airplane past the point of flying - and passengers wouldn't stand for it anyway.

It's a crap comparison, anyway - the TSA is better at finding toys than they are at finding bombs and weapons. Dogs and x-ray detectors could do just as well, and "alternative airports" could choose to have those.