All good theories. But when examining the damage to the basement of the WTC from the last terrorist attack, and seeing that it handled it without too much difficulty, and also, taking into account an experts comments on a radio program that I listened to, well I don't think so.
The expert commented that he was warning the US Government for years that an attempt would be made, and being an expert in demolition of this sort, he went on to explain the ins and outs.
Basically, the WTC could not have been brought down except by a controlled explosion from beneath, as was tried last time.
The expert went on that, had the terrorists placed the explosives slightly differently, the WTC would have come down last time.
So, after watching the south tower come down LIVE on television, when the damage was up top, and the fire was minimal, I am not buying the "plane knocked down the building" stuff. AND NOT BOTH TOWERS!