I've seen a very good clip that counters this argument.
The white "cloud" is just smoke from a damage engine after the plane hit trees and lamp poles before crashing into the Pentagon wall. The tail of
the plane is just visible to the left of the "smoke" for one frame only before the impact. It's impossible to tell from this distance what type of
airliner it is, but I'm fairly convinced that it is a 757. (Lumps of fuselage with the correct passenger jet insignia was scattered all over the
place).
Note that as the plane crossed the highway and grass, it knocked down several lamp poles. There is no way a single missile could do this. There is
nothing to be gained by conspiracy theorists claiming that a plane did not crash into the Pentagon. After all, the government NEEDED to take damage in
order to get support for its future wars.
youtube.com...