"Anyone at the beginning of the 1970s who forecast that terrorists would blow up jumbo jets in midair with all of their passengers on board, kidnap a head of state, run a boat filled with explosives aground on a crowded beach, set off a bomb weighing several tons in the heart of London's financial district, release nerve gas in a subway at rush hour, unleash biological weapons, hold a city hostage with a stolen or improvised nuclear weapon, or crash hijacked airliners into the Pentagon and the World Trade Center would have been dismissed as a novelist. Yet all of these events were perpetrated, attempted, or threatened."
RAND was the think tank that was commisioned by the Cabinet Committee to Combat Terrorism
http://www.rand.org/publications/randreview/issues/rr.08.02/thirtyyears.html
The Caliphate-a radical group of Turkish exiles living in Germany-also planned to launch a 9/11-style attack against the mausoleum housing Kemal Ataturk's remains.
All of these plots, however, had an antecedent in the she-ming of a supposedly psychologically imbalanced, wannabe assassin, who was a domestic, non-Muslim, conspirator.
Right now, there's a major Hollywood release based upon his story.