There was airport security before September 11, 2001. The planes were hijacked with relatively mundane items. The reason the hijacks succeeded was not because o

There was airport security before September 11, 2001. The planes were hijacked with relatively mundane items. The reason the hijacks succeeded was not because of the weapons that got past security. It was because up until that point, the standard operating procedure was to cooperate with hijackers. By the time anybody realised that they were not "normal" hijackings, it was too late.