http://www.cracked.com/article_17370_7-completely-unrealisti c-movie-plots-that-came-true_p2.html

In the March 2001 pilot episode of the show, the writers set out to create an over-the-top conspiracy theory and instead eerily predicted the future. In the episode, the main characters investigate and unravel a plot by rogue elements in the government to hijack a plane... and fly it into the World Trade Center.

Yep. Six months before 9/11.