The cursory security was easily bypassed, as it is believed that the September 11 terrorists got their knives through the X-ray machine simply by lying them on their edges between two books, so that to the inspector the blades appeared as nothing more than a dark line (Easterbrook, 168). Airline security is even more culpable because, prior to 9/11, there had been numerous warnings that improvements were necessary. For example, the report of the presidential commission on airline security, chaired by Vice President Al Gore, strongly recommended that the federal government begin certifying the contractors who run airport screening stations (Easterbrook, 169). Furthermore, "Red team" inspectors, who staged tests of airport security, found it alarmingly easy to smuggle weapons onto planes or enter the tarmac areas without identification (Easterbrook, 164). Due to the cognitive dissonance of the people in charge of security at airports, they were unable to stop the 9/11 attackers. When warned that their security was not strong enough, FAA officials gained information that was contradictory to that in their cognitive system. They used the technique of twisting beliefs to fit this data into their old cognitive model. Rather than realizing that terrorism had changed, they told themselves that because there had been no recent incidents of massive terror in the