JHC - in regards to #26 and #28, I respect what you're saying, and I'm not really trying to argue with you, but I think you overestimate the difficulty of flying one of these things. When I learned to fly I was checked out for solo flight after about 6 hours of instruction in a Cessna. Granted, that was a small Cessna, but I know several airling pilots and they have told me that essentially the mechanics of flying are the same in a big plane. They speed up and slow down much slower, but once they are at flying speed they are pretty easy to fly. I've talked with F-15 pilots who have said the same of fighter jets (the first thing I say to most pilots I meet is "how does that thing fly?") In regards to the Pentagon crash, too high and too low do extend infinitely, but you are disregarding the pilot's control. I regularly fly small planes a few feet off the ground - they don't just spontaneously change elevation unless there is a bit of wind, and a big plane takes a lot of wind to move it. Some people even skim their tires on the surface of a lake - that takes some precision. But flying in low isn't that hard.