Preventing future attacks
Way back in 1998, intelligence agencies concluded that, "a group of unidentified Arabs planned to fly an explosive-laden airplane into the World Trade Center." Three years prior to 9/11, the United States warned that "Osama bin Laden might use civilian airplanes in terror attacks." A presidential briefing on August 2006, warned of the possibility that passenger airlines could be used in terrorist attacks by al Qaeda. Even more specific, on August 16, 2001, a month prior to the attack, the FBI arrested Zaccarias Moussaoui on immigration charges after he was reported to be acting suspiciously while training at a flight school. The FBI speculated that Moussaoui might have been interested in flying a jet into the World Trade Center. NORAD for years had run drills to react to "planes being used as weapons against the World Trade Center and other U.S. high-profile buildings."