I'm not sure how much this topic has been discussed, searching around I find the odd pieces of information, but nothing concrete. Basically i'd like to know what others have found/determined in this area.
Thus far, i've identified at least three aerial vehicles in the vicinity of the WTC at some point that day that were caught on film.
A helicopter can be seen in very close vicinity to the towers about 15 seconds after the south tower is impacted, emerging from behind the North Tower.
There has been some discussion about this in various places, but studying a large amount of different films of the event, I find particularly, one thing to be worrying. The chopper is clearly visible in only one video that i've found and looks like unbroadcast footage (see above, if anyone can tell me the source of this footage, i'd be grateful). It plainly shows the chopper leaving the close surroundings a few seconds after impact two. I can not find any other clear image of this helicopter in any of the other multiple angles of broadcast footage. This is what I find incredibly hard to understand, the position/timing of the helicopter position is made quite clear in this video, yet simultaneous comparison with footage from a mutlitude of angles shows no image of it. One site I saw briefly mentioned this helicopter and said it was deliberately hiding in the smoke being blown from the North Tower. How is this possible? Wouldn't the smoke 'choke' an engine? Surely clean air to burn in combination with the fuel is a requirement as much as the fuel in its tanks to keep it in the air? Would the pilot also not think it too dangerous to hover near a burning building in almost zero visibility due to the smoke?
Another site claims that it was there to rescue people who had gone up to the roof, but couldn't due to the flames. What about the smoke? I think very few people would have been able to stand the roof for very long with all the smoke that's clearly visible.
This footage appears to have been shot from a chopper, though fairly obviously it's a different chopper to that pictured above (chopper appears from behind north tower, this film was obviously shot in front of the north tower). Where is the previously mentioned chopper in this image, or where would we expect it to be? Probably hidden behind the South Tower (which side? the impacted side?). How many choppers were actually in the area when the 2nd plane impacted?
There is clearly another completely different white plane/helicopter in the area (what many sites refer to as the command plane - 'GlobalHawk'. Could this really have been a passing plane? It's colour/movement vector are clearly visible in at least one piece of film. People will probably look at the photo and say it's a glitch/etc., but watch the film and you'll see it's definately a vehicle of some type. The impact of plane 2 is highlighted for time reference. Where is the previously mentioned helicopter in this image, or where should it be?
The (dark black?) helicopter seen against the background in the distance shortly before the collapse of the South Tower.
I understand all of this could amount to nothing, there must have been news choppers etc, in the air as well, but the fact that helicopter I mentioned first is all but invisible in all regularly shown public footage, when in my opinion it should be clearly visible in at least one shot of the multitude they regularly showed is a little odd imo.
If I had time I would give links to the videos and some other information I found, but that'll have to wait till a little later, as i'm out of time right now.