The term refers to the 19 al-Qaeda terrorists who hijacked four commercial airliners on September 11, 2001. Within this group, four individuals had received flight training to take control of the aircraft and navigate them toward their intended targets. The remaining 15 individuals acted as "muscle hijackers," tasked with subduing the crew and passengers. These perpetrators were not professional aviators but had acquired sufficient skills for the specific purpose of carrying out the attacks.
The four hijacker-pilots were Mohamed Atta, who flew American Airlines Flight 11 into the North Tower of the World Trade Center; Marwan al-Shehhi, who flew United Airlines Flight 175 into the South Tower; Hani Hanjour, who flew American Airlines Flight 77 into the Pentagon; and Ziad Jarrah, who flew United Airlines Flight 93, which crashed in a field in Shanksville, Pennsylvania, following a passenger revolt. These individuals undertook flight training at various schools in the United States, focusing on the skills necessary to control large jetliners in flight, rather than the full curriculum required for commercial pilot certification.
Grammatically, the keyword term functions as a noun phrase. In this construction, "September 11th" acts as an adjectival phrase modifying the noun "pilots." The significance of this specific phrase lies in its precise and loaded meaning; it exclusively identifies the perpetrators of the attacks, distinguishing them from the legitimate, professional flight crews who were the initial victims of the hijackings. The term encapsulates the identity of the attackers and the date of the event, serving as a specific historical designator.
