Hijackers in the September 11 attacks

According to the conclusions of a 2004 report of the 9/11 Commission, the 11 September 2001 attacks were carried out by 19 hijackers, and planned and organized by numerous additional members of al-Qaeda. The first hijackers to arrive in the United States were Khalid al-Mihdhar and Nawaf al-Hazmi, who settled in the San Diego area in January 2000. They were followed by Mohamed Atta, Marwan al-Shehhi, and Ziad Jarrah early in the summer of 2000 to undertake flight training in south Florida. The fourth pilot, Hani Hanjour, arrived in San Diego in December 2000. The "muscle hijackers", who were trained to help overpower and take over the aircraft, arrived in the spring and early summer of 2001.

Background
The idea for the 11 September 2001 attacks plot originated with Khalid Sheikh Mohammed, who had been active in the Philippines in the mid-1990s, and was an uncle of Ramzi Yousef, who was involved in the 1993 World Trade Center bombing.

Selection
Khalid al-Mihdhar and Nawaf al-Hazmi were both experienced and respected jihadists in the eyes of al-Qaeda leader, Osama bin Laden. Mihdhar and Hazmi both had previous experience fighting in Bosnia, and had trained during the 1990s at camps in Afghanistan. When Bin Laden committed to the September 11 attacks plot idea, he assigned both Mihdhar and Hazmi to the plot. Both were so eager to participate in operations within the United States, that they obtained visas in April 1999. Once selected, Mihdhar and Hazmi were sent to the Mes Aynak training camp in Afghanistan. In late 1999, Hazmi, Attash, and Yemeni went to Karachi, Pakistan to see Mohammed, who instructed them on Western culture and travel; however, Mihdhar did not go to Karachi, instead returned to Yemen.

Muscle hijackers
Mihdhar and Hazmi were also potential pilot hijackers, but did not do well in their initial pilot lessons in San Diego. Both were kept on as "muscle" hijackers, who would help overpower the passengers and crew, and allow the pilot hijackers to take control of the flights. In addition to Mihdhar and Hazmi, thirteen other muscle hijackers were selected in late 2000 or early 2001. All were from Saudi Arabia, with the exception of Fayez Banihammad, who was from the United Arab Emirates.

American Airlines Flight 11
Hijackers: Mohamed Atta (Egyptian), Waleed al-Shehri (Saudi Arabian), Wail al-Shehri (Saudi Arabian), Abdulaziz al-Omari (Saudi Arabian), Satam al-Suqami (Saudi Arabian).

Two flight attendants called the American Airlines reservation desk during the hijacking. Betty Ong reported that "the four hijackers had come from first-class seats: 2A, 2B, 9A, and 9B." Flight attendant Amy Sweeney called a flight services manager at Logan Airport in Boston and described them as Middle Eastern. She gave the staff the seat numbers and they pulled up the ticket and credit card information of the hijackers, identifying Mohamed Atta.

Mohamed Atta was heard speaking over the air traffic control system, broadcasting messages he intended for the passengers.

We have some planes. Just stay quiet and you'll be okay. We are returning to the airport.

Nobody move. Everything will be okay. If you try to make any moves, you'll endanger yourself and the airplane. Just stay quiet.

Nobody move please. We are going back to the airport. Don't try to make any stupid moves.

United Airlines Flight 175
Hijackers: Marwan al-Shehhi (United Arab Emirates), Fayez Banihammad (United Arab Emirates), Mohand al-Shehri (Saudi Arabian), Hamza al-Ghamdi (Saudi Arabian), Ahmed al-Ghamdi (Saudi).

A United Airlines mechanic was called by a flight attendant who stated the crew had been murdered and the plane hijacked.

American Airlines Flight 77
Hijackers: Hani Hanjour (Saudi Arabian), Khalid al-Mihdhar (Saudi Arabian), Majed Moqed (Saudi Arabian), Nawaf al-Hazmi (Saudi Arabian), Salem al-Hazmi (Saudi Arabian).

Two hijackers, Hani Hanjour and Majed Moqed were identified by clerks as having bought single, first-class tickets for Flight 77 from Advance Travel Service in Totowa, New Jersey with $1,842.25 in cash. Renee May, a flight attendant on Flight 77, used a cell phone to call her mother in Las Vegas. She said her flight was being hijacked by six individuals who had moved them to the rear of the plane. Unlike the other flights, there was no report of stabbings or bomb threats. According to the 9/11 Commission Report, it is possible that pilots were not killed and were sent to the rear of the plane. Passenger Barbara Olson called her husband, Theodore Olson, the Solicitor General of the United States, stating the flight had been hijacked and the hijackers had knives and box cutters. Two of the passengers had been on the FBI's terrorist-alert list: Khalid al-Mihdhar and Nawaf al-Hazmi.

Forensic remains of the five hijackers were found at the Pentagon, along with remains of the victims.

United Airlines Flight 93
Hijackers: Ziad Jarrah (Lebanese), Ahmed al-Haznawi (Saudi Arabian), Ahmed al-Nami (Saudi Arabian), Saeed al-Ghamdi (Saudi Arabian).

Passenger Jeremy Glick stated that the hijackers were Arabic-looking, wearing red headbands, and carrying knives.

Hijacker Ziad Jarrah also mistakenly broadcast messages intended for passengers over the air traffic control system:

Ladies and gentlemen. This is the captain. Please sit down. Keep remaining sitting. We have a bomb on board. So sit.

[...]

Uh, this is the captain. Would like you all to remain seated. There is a bomb aboard and are going back to the airport, and to have our demands met. Please remain quiet.

Jarrah is also heard on the cockpit voice recorder. In addition, DNA samples submitted by his girlfriend were matched to remains recovered in Shanksville.

Investigation
Within minutes of the attacks, the Federal Bureau of Investigation opened the largest FBI investigation in United States history, operation PENTTBOM. The suspects were identified within 72 hours because few made any attempt to disguise their names on flight and credit card records. They were also among the few non-U.S. citizens and nearly the only passengers with Arabic names on their flights, enabling the FBI to identify them and in many cases such details as dates of birth, known or possible residences, visa status, and specific identification of the suspected pilots. On September 27, 2001 the FBI released photos of the 19 hijackers, along with information about many of their possible nationalities and aliases. All the suspected hijackers were from Saudi Arabia (fifteen hijackers), United Arab Emirates (two hijackers), Lebanon (one hijacker) and Egypt (one hijacker).

The passport of Satam al Suqami was reportedly recovered "a few blocks from where the World Trade Center's twin towers once stood".; a passerby picked it up and gave it to a NYPD detective shortly before the towers collapsed. The passports of two other suspected hijackers, Ziad Jarrah and Saeed al Ghamdi, were recovered from the crash site of United Airlines flight 93 in Pennsylvania, and a fourth passport, that of Abdul Aziz al Omari was recovered from luggage that did not make it onto American Airlines Flight 11.

According to the 9/11 Commission Report, 26 al-Qaeda terrorist conspirators sought to enter the United States to carry out a suicide mission. In the end, the FBI reported that there were 19 hijackers in all: five on three of the flights, and four on the fourth. On September 14, three days after the attacks, the FBI announced the names of 19 persons. After a controversy about an earlier remark, U.S. Homeland Secretary Janet Napolitano stated in May 2009 that the 9/11 Commission found that none of the hijackers entered the United States through Canada.

Nawaf Al-Hazmi and Hani Hanjour, attended the Dar al-Hijrah Islamic Center in Falls Church, Virginia in early April 2001 while radical imam Anwar Aulaqi preached there. Through interviews with the FBI, it was discovered that Aulaqi had previously met Nawaf al-Hazmi several times while the two lived in San Diego. At the time, Al-Hazmi was living with Khalid al-Mihdhar, another 9/11 hijacker.

Cases of mistaken identity
Shortly after the attacks and before the FBI had released the pictures of all the hijackers, several reports appeared claiming that some of the men named as hijackers on 9/11 were alive, and were feared to have been victims of identity theft. These cases, however, turned out to be instances of mistaken identity.