Yes, thats about the size of it, that is why my area of expertise is in group psychopathology.
I would dispute whether another 767 was used however.
http://www.youtube.com/watch?v=Lc5inmZqGu8
Ah ok, I understand. So that's why you like delve so deep into trutherland! It's rich hunting grounds for your study interests!
Your problems with these conflicting witness testimonies are easily explained:
Every time several people witness an accident, there will be several versions of what they saw, and some will be mutually exclusive. A great concern every time is that the mind fills in the blanks within the recorded memory. People saw a plane. Upon being asked for specifics, they kinda "roll back the film", and when there is no distinct memory of what the plane looked like - markings, windows, colour - they are likely to fill in something, whatever seems likely to the. The second time around, those imagined fill-ins have become part of the recorded memory.
I was once knocked over by a car while riding my bicycle, was rendered unconscious for close to a day, and had no memory of the accident. But I was asked many times up until what moment I do remember. Today, I clearly remember the guy behind the wheel of his red car, squinting because the sun was low, turning towards me.
Of course in reality the car wasn't red.
It is very easy to understand why people would not consciously see windows on a plane flying around 500mph about 800-1000ft above street level: depending on bank, you can see the sides of a plane sufficiently clear only when you see it from the side; in which case you are either a long distance away (one of the witnesses in the above video was in Brooklyn), or more likely than not the flight path will be obscured most of the time by other buildings, and you only have fractions of a second to see. Or you are closer to the flight path, in which case you mainly see the belly of the plane.
I live about 25km away from an airbase that is home to the NATO E-3A wing. The planes are mostly 707-based: AWACS with a very pronounced radar "mushroom" on their back, tankers, and rather ordinary cargo- and personell transporters. It is not rare that one of them flies low by my house en route to landing. Just the other day, I and a friend saw one maybe 2500ft away, and we discussed it (how far, how noisy), and guess what: neither of us remembered if it had radar or not, and we both had doubts whether they have 2 or 4 engines. Ask me for markings? Windows? I could not tell from any of the many fly-bys I have witnessed. They are grey. That much I am sure.
By the same reasoning I would be very skeptical towards any witness who reports having seen a "United Airlines" plane, or one with AA-markings. I'd suspect most filled that information in hours if not days and weeks after the event.
