However, international terrorism-especially air piracy-wasn't unheard of in the 1970s.
"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