I will admit that it took me a couple of days before I was thinking how 'convenient' the military actions of 9/11 were. Convenient to the oil-funded politicians who wanted to invade Iraq for daring to trade their oil in a currency other than that of a country who had done them little good. Convenient to the political movement that wanted far greater control over the US public.
I don't believe the US Government's story of the events of that day. (I think that to believe in things like an intact passport floating down from one of those aeroplanes, you have to be so gullible that you deserve the loss of your freedom.) Who conspired with whom, who had foreknowledge of what, we might never know, but the official conspiracy story (like the UK Government's conspiracy story of 7/7/2005) is too full of fabrications and error to hold together.
Because the American people had not had attacks on their homeland for so many years, the events of that day did shock them. However, I think the main perpetrator of terror for the people of the USA is their own government. Had the events happened in the UK, where most adults have lived with terrorism from Irish separatists for a long time, we would not have been terrified, simply angry. I believe that without the actions of core people in the US Government, that would have been the result of 9/11. The "War on terror" really is a "war of terror" perpetuated on the citizens of the USA such that they now have far less rights than they had when they revolted against the British and declared righteous independence.