How would it have ever survived (the film would've been in a camera etc)
Thousands of people were incinerated and blown to pieces - I would think the plane was probably inserted into someone's pic from the rooftop and the "date" was easily manipulated too.
Also, that day was a beautiful day in the city and he's dressed too warm, especially the hat!
It's sick really, but there will probably me more of this type stuff.
WORLD TRADE TOWERS OFFICIAL SITE- pages 4 & 5 show where the orig pic was probably taken