KSM acknowledges formally joining al Qaeda, in late 1998 or 1999, and states that soon afterward, Bin Ladin also made the decision to support his proposal to attack the United States using commercial airplanes as weapons. Bin Ladin summoned KSM to Kandahar in March or April 1999 to tell him that al Qaeda would support his proposal. The plot was now referred to within al Qaeda as the “planes operation.” No one else but KSM, Bin Ladin, and Atef were involved in the initial selection of targets.
Much of his activity in mid-1999 had revolved around the collection of training and informational materials for the participants in the planes operation. For instance, he collected Western aviation magazines; telephone directories for American cities such as San Diego and Long Beach, California; brochures for schools; and airline timetables, and he conducted Internet searches on U.S. flight schools. He also purchased flight simulator software and a few movies depicting hijackings. To house his students, KSM rented a safehouse in Karachi with money provided by Bin Ladin. The course in Karachi apparently lasted about one or two weeks. According to KSM, he taught the three operatives basic English words and phrases. He showed them how to read phone books,interpret airline timetables, use the Internet, use code words in communications, make travel reservations, and rent an apartment. KSM told them to watch the cabin doors at takeoff and landing, to observe whether the captain went to the lavatory during the flight, and to note whether the flight attendants brought food into the cockpit.
Although Bin Ladin, Atef, and KSM initially contemplated using established al Qaeda members to execute the planes operation, the late 1999 arrival in Kandahar of four aspiring jihadists from Germany suddenly presented a more attractive alternative. The Hamburg group shared the anti-U.S. fervor of the other candidates for the operation, but added the enormous advantages of fluency in English and familiarity with life in the West, based on years that each member of the group had spent living in Germany.
KSM played a key role in facilitating travel for al Qaeda operatives. KSM provided his operatives with nearly all the money they needed to travel to the United States, train, and live. The available evidence indicates that the 19 operatives were funded by al Qaeda, either through wire transfers or cash provided by KSM, which they carried into the United States or deposited in foreign accounts and accessed from the United States. KSM, Binalshibh, and another plot facilitator, Mustafa al Hawsawi, each received money, in some cases perhaps as much as $10,000, to perform their roles in the plot. According to KSM, the Hamburg cell members each received $5,000 to pay for their return to Germany from Afghanistan after they had been selected to join the plot, and they received additional funds for travel from Germany to the United States.
Sheikh Mohammed's arrest in Rawalpindi, Pakistan on March 1, 2003 marks one of the most important breakthroughs in the fight against al-Qaeda. The two key factors leading to his arrest was a bribe to an Al-Qaeda operative in the amount of $27 million, as well as information gained from the NSA electronic surveillance network, Echelon. Although the arrest was solely a Pakistani operation the FBI observed the arrest and was to a large degree invovled in the interrogation process. Pakistani officials claim that KSM remained in Pakistan for 3 days and then was subsequently moved to an undisclosed location by US officials.