I'm loath to comment again, this thread has become rife with "interesting ideas" and more than a little personal philosophy.
I am curious as to your reference to "concrete blast wall" J. I have a civil engineering backgroud, and that I am aware of there was no construction in either the World Trade Center or the Pentagon that employed that type of construction. I know for a fact the the World Trade Center Towers were an innovative construction method, comprised of a semi-traditional steel girder construction with a uniquely employed exterior steel interlocking structural panel and glass construction. As memory serves, the Pentagon was a conventional mix of CMU, concrete, steel, wood and drywall construction methods.
A projectile weighing something on the order of 150,000 - 200,000 lbs (or a bit more depending on the aircraft type), laden with petroleum fuel and moving anywhere from 185 - 400 MPH ( a guess as to their velocity, given their manuvering at relatively low altitude) will put a big hole, very big in virtually any conventionaly constructed building.
I'm not one to defend the current, or for that matter most of the preceding, governmental administrations, quite the reverse. But, I have a hard time believing that even G.W. and his political and industrial cronies could have instructed their minions to coordinate an event this heinous on American soil.
