5) Newsweek twice reported that top Pentagon officials had got a warning of the impending attack on September 10th, and cancelled their flights for the next day. This confirms that these officials knew both the locations of the imminent attack and the method of using jetliners as bombs.
"On Sept. 10, NEWSWEEK has learned, a group of top Pentagon officials suddenly cancelled travel plans for the next morning, apparently because of security concerns." "NEWSWEEK has learned that while U.S. intelligence received no specific warning, the state of alert had been high during the past two weeks, and a particularly urgent warning may have been received the night before the attacks, causing some top Pentagon brass to cancel a trip. Why that same information was not available to the 266 people who died aboard the four hijacked commercial aircraft may become a hot topic on the Hill."
Sources - Newsweek September 24th - Newsweek September 13th