I'd like for you to show me where I did that. Should be great.
As for his question, any theory that involves the plane hitting the building and than the flash is less probably because it is impossible. The flash happened before the plane hit the building.
http://www.youtube.com/watch?v=s8VFV8MvqxE&feature=related
If one were to ask me if that really is a missile however, I would say
I am split 50/50. On one hand, it just seems to crazy to be true. Doesn't seem like it would be necessary (although perhaps they thought the risk of someone noticing the missile is outweighed by the risk of some plane parts falling to the ground and did not want to take that change). Also I have looked and not found someone that has laid out a good math model for what we should expect a plane to when colliding with the building. If someone knows of one I would like to see it. I'm honestly not sure it would have caused that much damage, given the little amount of time it would have had. But on the other hand, I just don't know what it is. Can not be a reflection does not appear to be a static discharge. And any theory that relies on the plane connecting first is impossible. Also you have to deal with whatever that flame is out of the back. There is also a flash at the North tower as well. You can see it here at the 14 second mark or so.
http://www.youtube.com/watch?v=zCGNZzdwEiM&feature=related
I posted this truly as a question because I don't know what those flames or flashes are.