@Shard
They made a mistake because they had to rush.
If you had bothered to actually read my post, you would have picked up on the fact that
it takes more time and effort to put that mistake in the video than it takes not to have the mistake in there at all. If they were in a rush or lazy, that "mistake" wouldn't be there. Of course, this is going along with your delusion (or perhaps misperception) that the wing is ever behind either tower. I'll give you the benefit of the doubt, maybe you actually see it disappear because there's a lot of grey-on-grey, or maybe your monitor's color fidelity is poor. I promise you, I've watched those few seconds about 20 times, and it's very clear the wing is always visible.
It's nearly impossible to fake an image of the world, mostly because you have to match the quality and the lighting of the original (both of which are pretty hard to do). Faking a video is even harder. Faking 50 videos is even harder, especially when 50 different random people own the originals. Which seems more likely to you:
1) The government found, confiscated and doctored 50+ different videos from private citizens and organizations before they uploaded any to youtube, doctored them to put a 3d plane in the video, added mistakes to the video on purpose by accident, gave the videos back to the original owners (because multiple people upload their versions to youtube), and made 100 people on the flight disappear, all within five minutes of the event (because many of those clips were broadcast live), then within the next year they convinced every new yorker on the street to lie about what they saw and 100% of them complied, or...
2) A plane hit the building.
The government has spouted enough retarded BS about the issue, you've got plenty to work from without having to make this garbage up. When you say things like "Hey, I know thousands of people saw it and a plane actually disappeared and the people on it actually disappeared and there are dozens of videos showing the same thing, but this ONE CLIP looks kinda sorta fake so I'm going to ignore everything else" you're only lowering your own credibility. It's the same reason nobody takes creationists seriously.