I'm not persuaded that the published clip is genuine; more likely a very clever and imaginative bit of editing - and well done at that. The flypast could almost certainly be valid. What's happening on the ground is probably valid. However for it all to be one authentic clip - shot in real time does not pass scrutiny for many of the reasons already stated above. There is also a surreal aura to the entire sequence; the lighting, the speed (obviously slowed down - but why?). It just doesn't ring true.
There is one further question mark. As far as I am aware, this is the only published clip of the event. If so, that seems very strange given that almost everyone on the ground would have been filming, and we should be seeing multiple contributions from other sources at other locations in the occurance. They may yet appear, and if they do - then I'll moderate my reservations, but until that happens, well, I will hold by my stated reaction so far. Sorry - nice bit of work but ....