It's a little hard to explain exactly what it looks like, so I'll try to give "directions". Do you see what looks like a ramp off a highway, elevated from the rest? You can see a truck driving by, but before it there is another object coming by at a downward angle. That's what I theorize as the plane. The status of the Pentagon and the Twin Towers are completely different, which could be a reason for the confiscation of the tapes. As for the sand, that is interesting. Could it be used to suck up any possible gasoline or other fluids?