The Enigma of The Fires

Has anyone here carefully watched the new video footage of the Twin Towers, mostly from the perspective of the North Tower? I refer to the "What We Saw" home movie that has just been put on the net.
This clearly shows that contrary to what some 911 Truth people have said, that the fire worsens rapidly - very far from going out. Given that I don't live in New York, I am guessing that the side of the building I am speaking of is the Western face of the tower - but anyhow, you can see the gaping hole (think that is the North face) and when the video starts only a few puffs of smoke on this Western face (forgive me if you know it not to be West, I as said don't live in New York).
Anyhow, the rapid progression of the fire is easily seen by watching this Western face. Indeed it begs more questions than it answers. The whole tower above the damaged section is soon smoking, and we see smoke coming out even at the roof area. Now I just don't understand how the fire spread so rapidly from the damage some 15 floors down, all the way up to the top. Can someone explain this to me? By the time that the South Tower collapses (we see only the enormous dust clouds on this) the whole North Tower is a black smoking wreck above the damage, and there are areas of very fierce burning flames - on the face that at the beginning was outwardly least affected by what had happened.
Another point of interest is just before the collapse of the South Tower, the camera points to street level, where the existance of smoke is documented. Unfortunately the collapse of the South Tower becomes the focus of the cameraman's attention, and the lens turns to the dust clouds from that.
The existance of another third aeroplane is clearly documented in this footage too, not just the police helicopter, so this video is very interesting from that perspective.
Anyhow to summarise. This video appears to contradict the 911 Truth claim that the fires in the towers "were almost out", but on the other hand, how in heaven's name did these conflarations spread so quickly through the floors? What do we make of the dust at street level before the collapse of the first tower, and what is the third aeroplane.
Finally, though I am not sure of its real importance, the lady making the video seems to think that the second plane was a military plane. Now that is interesting. Why would she think that? This is the first time I have anyone suggest this, but this is an eyewitness while the thing was happening. That indeed is a very interesting comment.