Various conspiracy theories allege that certain institutions or individuals had foreknowledge of the September 11 attacks in the United States in 2001. Some of the primary debates include whether the Bush administration or the United States Armed Forces had awareness of the planned attack methods, the precise volume of intelligence that American agencies had regarding al-Qaeda activities inside the United States, whether the put options placed on United Airlines and American Airlines and other trades indicated foreknowledge, and why the identities of the traders have never been made public.
Additional facets of the theories include debate as to whether warnings received from foreign agencies were specific enough to have warranted preventive action, whether domestic intelligence about planned al-Qaeda attacks was thorough enough to have mandated intervention, the extent to which the alleged hijackers were under surveillance prior to the attacks, and whether Mossad or the Pakistani Inter-Services Intelligence were aware of an imminent attack.
Using planes as missiles
Immediately following the attacks, President George W. Bush stated that: "Nobody in our government, at least, and I don't think the prior government, could envision flying airplanes into buildings", and National Security Advisor Condoleezza Rice claimed: "no one could have predicted that they would try to use an airplane as a missile". An Air Force general called the attack: "something we had never seen before, something we had never even thought of." A few days after the attacks, FBI Director Robert Mueller announced: "There were no warning signs that I'm aware of that would indicate this type of operation in the country." However, Mueller noted that an FBI agent in Minneapolis said Moussaoui might be that type of person that could fly something into the World Trade Center. Mueller said this warning should have been followed more vigorously.
Some mainstream media reports have conflicted with these statements, claiming that the FBI, CIA and Executive Branch knew of the threat of planes being used as missiles as early as 1995, following the foiling of the Bojinka Plot. In September 2002, one year after the 9/11 attacks, The Chicago Sun-Times reported that:
The FBI had advance indications of plans to hijack U.S. airliners and use them as weapons, but neither acted on them nor distributed the intelligence to local police agencies. From the moment of the September 11 attacks, all high-ranking federal officials insisted that the terrorists' method of operation surprised them. Many continue to stick to that story. Actually, elements of the suicide hijacking plan were known to the FBI as early as 1995 and, if coupled with current information, might have uncovered the plot.
The Pentagon Mass Casualty project (codenamed Pentagon Mascal) was a contingency exercise that was held in the Office of the Secretary of Defense conference room between October 24 and October 26, 2000. The exercise required emergency response teams, members of the defense protective services, and U.S. government officials to conduct emergency simulations in preparation for a possible plane crash into the Pentagon.
The book The Terror Timeline includes numerous articles that are often cited to suggest that the method of flying planes into buildings was known by U.S. officials: