Sorry, I know I'm breaking the promise I made to myself not to weigh in on this conspiracy discussion, but I did do my moment of silence and I do think I need to make at least one comment here.
I recall seeing the video of American Airlines Flight 77 hitting the Pentagon, and the angle of descent was fairly steep if you project its line of flight backward (essentially it looks like someone aiming for the building and hitting a bit low), but that is only if you trust the video. Once you distrust the video (as I suspect you do), then all bets are off. Anyway, I'm no expert, but I don't see how the ground effect would matter if the plane started higher (100-200 feet up) and essentially plunged nose first into the ground.
Also, what happened to the passengers listed as being on the flight who were listed as dead? Did they never show up for the flight? Kidnapped before the scheduled flight and killed by the government? One of the dead was Barbara Olson, the wife of the prominent Bush solicitor general Ted Olson. How does the conspiracy explain the disappearance of these people, including such a prominent public figure?
I wonder if there is airline video of the plane boarding and taking off. Then the conspiracy would have to account for what happened to a large airplane full of people if it did not crash into the Pentagon as history records.
Look, it is good to be skeptical up to a point. But there has to be some balance between what might be conspiracy, what might be incompetence, and what might be coincidence. I just don't see the motive or coordination for the 9/11 conspiracy as described, just a wide-ranging rejection of anything labeled the official version. That is not to say that certain politicians have not exploited 9/11 for their own gain - but it does not therefore mean that they planned the event or actually wanted all of those people to die.