|United Airlines Flight 93
The Boeing 757 departed 08:42 from Newark, New Jersey, for San Francisco. The hijackers struck three-quarters of an hour later.
The plane crashed at 10:02 into an empty field in Shanksville, Pennsylvania, killing all 44 on board, including seven crew.
The flight took off 25 minutes late, and news of the other hijackings was already beginning to spread. The hijackers stormed the cockpit moments after a warning was sent to the pilot.
According to a call from on board, passengers voted to storm the cockpit. Sounds of a sustained assault can be heard on the plane's voice recorder. A passenger can be heard shouting: "In the cockpit. If we don't we'll die."
The hijackers were forced to ditch the plane early. It landed in an empty field, 20 minutes short of its Washington target.
Flight 93 had only four hijackers - Lebanese-born Ziad Jarrah, and Ahmed al Nami, Saeed al Ghamdi and Ahmad al Haznawi, from Saudi Arabia. Mohamed al Kahtani, thought to be the fifth one, had been refused entry to the US the previous month by suspicious immigration staff.
Newark to San Francisco
Take-off: 0842 EDT
Dead: 40 plus four hijackers