Don't buy off on the flight simulators/MS software theories. I'm a former fighter pilot and, as such, don't have a whole lot of time in auto pilot. Although I'm not au fait with 757/767 characteristics,there's one thing I know for sure--it ain't easy to drive an airplane (ANY airplane) into a target (Pentagon) in a shallow dive with continuously changing airspeed and AOA perameters--the game enthusiast probably would have faced that scenario, but the pro (or well-trained amateur) would have the skill to control a/s and AOA significantly simplifying the problem. A level approach against the WTC would be easier, but still, in my humble opinion, beyond the capabilities of a guy with very little no-**** airplane driving experience.
When the guys go out to get even, I sure wish I could join 'em.