|United Airlines Flight 175
The Boeing 767 left Boston's Logan Airport at 08:14. About 30 minutes later it was hijacked.
At 09:03 it crashed into the south tower of the world Trade Center, travelling at 540mph.
All 65 people on board died instantly. The plane hit the 81st floor, carving a hole from the 77th to the 85th floors. Some on the upper storeys were able to escape down the one remaining undamaged stairwell. Of the estimated 8,600 occupants, about 600 died in the tower.
Armed with knives and mace, the hijackers took control after forcing their way into the cockpit.
Passenger Peter Hanson rang his father, Lee, saying he thought the plane had been hijacked. Minutes later he rang again. His final words: "If it happens, it'll be very fast - My God, my God."
The hijackers were Fayez Banihammad, from the United Arab Emirates, Mohand al Shehri, Hamza al Ghamdi and Ahmed al Ghamdi, from Saudi Arabia.
The pilot was Marwan al Shehhi, also from the UAE, a longtime friend of Atta.
Boston to Los Angeles
Take-off: 0814 EDT
Dead: 60 plus five hijackers