The hijackers on the September 11, 2001 attacks used a combination of weapons and tactics to take control of the planes. Primarily, they wielded knives and razor blades, which they likely carried on their person or in carry-on luggage. These knives were within the FAA regulations at the time, which allowed knives up to four inches long on airplanes, so even if detected, they would have been returned to the hijackers rather than confiscated
. In addition to knives, the hijackers used mace (a chemical spray) and threatened passengers and crew with bombs to intimidate and control them. Eyewitness accounts from passengers and flight attendants on United Airlines Flight 175 reported the use of knives, mace, and bomb threats during the hijacking
. The hijackers stabbed flight attendants and crew members to gain access to the cockpit, which was locked during flight. They may have used the violence to obtain the cockpit key or force the crew to open the cockpit door. The hijackers also used the threat of bombs to keep passengers subdued
. On United Airlines Flight 93, hijackers similarly carried knives and made bomb threats over the intercom to control passengers
. In summary, the hijackers used:
- Knives and razor blades (within FAA-allowed size limits)
- Mace (chemical spray)
- Threats of bombs
These weapons and tactics enabled them to overpower the crew and passengers and take control of the aircraft
