The web cam captures a lot of planes. At night the camera is set to a longer exposure, which makes the planes leave trails. This is also happening with these purple streaks, which are just bugs that are very close to the camera, and are lit by a light close to that camera.
We know this because they look exactly like thousands of photos of "rods" - an optical phenomena cause by insects (or sometimes birds) and long exposure. You can find many examples with an image search for insect+rods
A large part of the reason that 9/11 conspiracy theories persist is simply that people not understanding the physics of the collapse. I was talking to a conspiracy theorist a while back, trying to explain why the towers collapsed. I said that the floor trusses were heated until they sagged, then they pulled away from the walls. Here's a visualization of this with the floor slabs removed so you can see the trusses.
He asked why would they pull away from the walls. They were not any heavier. They were still attached to the walls. It was still the same mass being supported by the ends of the truss, so why would it pull? It made no sense to him.
I realized I'd not really given it much thought myself. I had to...
Mystery Solved by Fox 6 News in a later video, lights at the courthouse illuminating a flock of seagulls.
The original video is set for night exposure, which creates trails behind the brightly lit seagulls. The cars in the video have similar trails
If you apply a persistent image filter to the seagulls you get:
Some people still insist the traffic camera video shows something a lot higher and larger than seagulls, but in this next video I compare them to the courthouse seagulls in size, which makes them only a few hundred feet away.
In a recent interview with the BBC, Roland Angle claimed that NIST did not have any explanation for the 2.25 seconds of essentially free fall descent observed during the collapse of World Trade Center Building 7, saying:
This is a long discussion I had with Patrick Roddie, who firmly believes that the government is engaged in a secret geoengineering program with "chemtrails". Patrick runs a web site StopSprayingUs.com, and frequently appears at chemtrail/anti-geoengineering events.
We start out talking about the physics of contrails, then move on to the problems of sampling for aluminum, satellite images of clouds, halos and sundogs, and geoengineering proposals
The column in the center of the photo (by Sam Hollenshead) has been cut at an angle, presumably during the cleanup process. Yet Architects and Engineers for 9/11 Truth (AE911) still insist it was cut before the building fell, and looks nothing like a normal cut, and hence is evidence of thermite. Here's an AE911 slide they used just a few weeks ago:
Here's Richard Gage, head of AE911, discussing this: