The hijackers in the September 11 attacks were 19 men affiliated with al-Qaeda. 15 of the 19 were citizens of Saudi Arabia, and the others were from the United Arab Emirates (2), Egypt and Lebanon.[1] The hijackers were organized into four teams, each led by a pilot-trained hijacker with three or four "muscle hijackers" who were trained to help subdue the pilots, passengers, and crew.
The first hijackers to arrive in the United States were Khalid al-Mihdhar and Nawaf al-Hazmi, who settled in San Diego County, California in January 2000. They were followed by three hijacker-pilots, Mohamed Atta, Marwan al-Shehhi, and Ziad Jarrah in mid-2000 to undertake flight training in south Florida. The fourth hijacker-pilot, Hani Hanjour, arrived in San Diego in December 2000. The rest of the "muscle hijackers" arrived in early and mid-2001.