Not more than 15 minutes after takeoff, the hijackers injured two people, murdered one, and breached the cockpit while forcing the passengers and crew to the rear of the aircraft against their will.

The assailants quickly overpowered both the captain and the first officer and possibly killed them, allowing lead hijacker Mohamed Atta to take over the controls, having intensively trained as a pilot in the lead-up to the attacks.

They realized the plane had been hijacked when Atta's falsely reassuring announcements for the hostages were transmitted to air traffic control instead of the cabin's PA system as intended.

Two flight attendants were able to contact American Airlines and passed along information relevant to the situation, in particular casualties suffered by the passengers and crew.

The impact was witnessed by countless people in the streets of New York City as well as the nearby state of New Jersey, but few video recordings captured the moment.

Seventeen minutes later, United Airlines Flight 175 crashed into the World Trade Center's South Tower at 09:03, instantly dispelling any notion it was accidental.

While the recovery effort at the World Trade Center site did lead to the discovery and identification of body fragments from certain individuals who boarded Flight 11, many have not been identified.

[6] The crew members were Captain John Ogonowski (50), First Officer Thomas McGuinness Jr. (42) (a former Navy fighter pilot), purser Karen Martin and flight attendants Barbara Arestegui, Jeffrey Collman, Sara Low, Kathleen Nicosia, Betty Ong, Jean Roger, Dianne Snyder, and Amy Sweeney.

[10] Family Guy creator Seth MacFarlane had been scheduled to be on the flight but overslept due to a hangover and arrived at the airport too late.

[13][dubious – discuss] Mohamed Atta, the ringleader of the attacks, and fellow hijacker Abdulaziz al-Omari arrived at Portland International Jetport in Maine at 05:41 Eastern Daylight Time on September 11, 2001.

Out of concern he was racially profiling Atta as an Arab terrorist, Tuohey did not budge or rise to his hostility, and simply told him that he would better hurry if he did not want to miss the flight.

[6] When they checked in, the Computer-Assisted Passenger Prescreening System (CAPPS) selected Atta for extra luggage scrutiny, but he boarded without incident.

[20] Shortly before takeoff, American Airlines flight service manager Michael Woodward walked aboard for a final check.

[33][34][35] It is unknown how the hijackers gained access to the cockpit; FAA rules at the time required that the doors remain closed and locked during flight.

[18][37] Atta apparently tried to make an announcement to the passengers, but keyed the wrong switch and instead his voice was picked up and recorded by air traffic controllers.

[i] After Atta's transmissions and the inability to contact the airliner, air traffic controllers at Boston ARTCC realized that Flight 11 was being hijacked.

Three minutes before impact, Atta completed his final turn toward Manhattan,[28] flying south over the city in the direction of the World Trade Center.

At 08:46,[j] flight attendant Amy Sweeney panicked that her plane was "flying way too low" just as Atta deliberately crashed into the North Tower.

[60][61] Light-to-moderate damage was reported on every floor from ground level to the 92nd, including collapsed walls, missing ceiling tiles, severed wires and smashed windows.

Prevailing winds from the northwest caused the top of the South Tower to become engulfed by the thick smoke pouring southeast, and a number of employees at that altitude reported that the fumes began filtering into their floors alongside the intense heat.

French cameraman Jules Naudet, who was filming a documentary about the FDNY, rode with Battalion 1 to investigate a suspected gas leak in a storm drain at the intersection of Church and Lispenard streets, where he caught the only known clear footage of the plane flying into the tower.

Just south of the World Trade Center, the New York City-based television station WNYW had been filming in nearby City Hall Park when Flight 11 crashed into the tower offscreen.

[68][69][70] A webcam set up by Wolfgang Staehle at an art exhibit in Brooklyn to take images of Lower Manhattan every four seconds also captured stills of Flight 11 flying towards the North Tower and the explosion that followed.

[74] Seventeen minutes after the first impact, the World Trade Center's South Tower was hit by United Airlines Flight 175, confirming that the crash was deliberate.

[81] Rescue workers at the World Trade Center site began to discover body fragments from Flight 11 victims within days of the attack.

Some workers found bodies strapped to airplane seats and discovered the remains of a flight attendant with her hands bound, suggesting the hijackers might have used plastic handcuffs.

[84] They identified two other Flight 11 victims, including purser Karen Martin, in 2006, while other unrelated body fragments were discovered near Ground Zero around the same time.

Soaked in jet fuel, it was picked up by a passerby who gave it to a New York City Police Department (NYPD) detective shortly before the South Tower collapsed.

The bags contained papers from Atta's studies in Germany and Egypt; Alomari's international driver's license and passport; a videocassette for a Boeing 757 flight simulator; and a folding knife and pepper spray.

[96] On April 26, 2013, a piece of the wing flap mechanism from a Boeing 767 was discovered wedged between two buildings at Park Place, near where other landing gear parts were found.