my biggest problem with the idea of the government pulling off a conspiracy like this is I don't have enough faith in them that enough people could coordinate such an event and manage to keep it quiet. Go down to the DMV and you'll see what I mean
I thought the idea of the government staging terror attacks to garner public support was wacko as well until I was reading a book about Eisenhower and it talked about how he seriously considered staging attacks on Americans to garner support for invading Cuba, so its not completely out of the realm of possibility. I still don't buy 911 was a government/CIA operation but God help us if it was.
You can read about Operation Northwoods
here