A quick glance at that Youtube does make me think it's fake - it's remarkably smooth for something that's been "slowed down", and the plane does indeed have a CGI quality to it.
So either
It is as presented to News Media, in which case OMG inside job!!
or
It's a bit of fake that's either been made to "prove" that it was a hoax, or the 9/11 conspiracy folk have seized on it as further "proof" of their theories.
or it's just a quirk of the video / enhancing technique used.
Lovely example of misunderstanding technology here :
http://youtu.be/5Lueue1FyR4Claimed to be an invisibility cloak, because the running soldier gradually appears out of nowhere.
Much more likely to be a result of the video compression codec at low bit rate initially ignoring and then trying to cope with a soldier wearing camouflage running rapidly into frame.
Ian