Three to five hijackers per plane
US investigators believe that three to five hijackers were aboard each of the four airliners used in yesterday’s attack.
They believe the hijackers were trained pilots and had been carrying small penknives, which were used to stab and kill crew in order to access the cockpit.
Experts say passengers could easily pass through airport security carrying a knife if it were small enough. Investigators are following all possible leads as to who carried out the attacks.
