Conspiracies often involve a division of labor. A conspiracy as well-orchestrated as the September 11th four-plane attack required that the conspirators engage in different tasks . It needed conspirators to gather advance intelligence. It needed conspirators to provide logistical support. It needed conspirators to break into the cockpits and take control. It needed conspirators to commit suicide by flying the planes into their targets. These tasks, which required different competencies and qualifications, necessarily did not have to be performed by the same conspirators.

First, the intelligence mission. The conspiracy had to be pieced together a picture of how the planes to be commandeered were protected so that assault teams could be trained and equipped. It would need information on how flight crew and attendants restricted entry into the cockpit, how they communicated with each other and the ground, the periods during the ascent when the cockpits would be vulnerable to a take-over, the location of transponders and other ground-air communication devices and how the planes could be navigated and re-routed to new destinations. Such reconnaissance required sustained observation of the flight crew and cockpit entry. The intelligence-gathers therefore would have to be individuals who could travel first- class on domestic flights and converse with crew members without arousing undo suspicion. Aside from passive observation and probes on the planes themselves, they could also learn about airline procedures by conversing with pilots, instructors and trainees at flight schools and by acquiring flight manuals, articles and training videos about the aircraft.

At airports, the conspiracy would have to assess the effectiveness of the screeners to determine how to disguise or smuggle on board the equipment and weaponry needed by the assault teams. Could this gear be carried past screeners by the hijackers themselves or would it needed to be smuggled and cached by accomplices in the transit areas? The intelligence gatherers would need to test the vulnerabilities various airports with proximate objects (even though being repeatedly photographed by security cameras might limit the tenure of their service.)

A number of the known conspirators were involved in this intelligence mission, including Mohamed Atta, Marwan al-Sherri, Ziad al-Jarrah and Hani Hanjour. These men had enrolled in different flight school in Florida and Arizona, trained on a number of flight simulators and visited a half-dozen private airports rented small aircraft. Atta had purchased flight manuals and video tapes of flight decks. So they had both a background perspective and a plausible pretext for asking question about about airliner procedures. These men also made many first-class flights on Boeing 757s and 767s where they would have the opportunity to watch and chat with flight crews.

Second, the logistic mission. The conspiracy needed to cocoons the members of the four assault teams in different cities in America for three months while they awaited September 11th. It had to rent rooms, open bank accounts, establish communication channels, furnish them with driver licences or other photo identifications and reserve tickets for them on the targeted flights.

The conspirators who made these, and other arrangements, needed some familiarity with the areas in which they were cocooning the hijackers as well as credentials which would allow them to make transactions without arousing suspicion. They could have been some of the same men who were engaged in the intelligence-gathering mission or different individuals.

Atta and al-Shehhi, for example, arranged lodgings, bank accounts and flight reservations in Florida. Khalid al-Midhar was involved in similar activities in southern California. Fayez Ahmed arranged bank account and credit card funding for the hijackers. Like the intelligence- gatherers, these arrangers would necessarily expose themselves by signing leases, car rental agreement, bank papers, etc.

Third, the assault mission. The conspiracy needed to organize and train four teams of hijackers. These men had to be capable of rapidly gaining entry of the cockpits, disabling any opposition and taking over the controls of the Boeing 757s and 767s. The pilots in these teams required further skills. They had to be able to maneuver their planes in various weather conditions— the weather for September 11th could not be predictable in August when the tickets were purchased— and navigate the planes to their targets. They also had to be willing to kill themselves and innocent people by crashing airliners laden with jet fuels into buildings. (The other members of the assault team did not need to know it was a suicide mission). The members of these assault teams, unlike the intelligence gatherers and logistical arrangers, did not require linguistic or social skills. The conspiracy had an interest in shielding them from any attention or watch list that might interfere with their mission.

The identification of the 19 men who formed these assault teams has not been established by any DNA or forensic evidence. Nor did anyone aboard the doomed aircraft identify them. The names under which the tickets were booked on the Internet are known from the airlines' computers, but these names may not match their true identities.

The identity confusion. Conspirators often act deceptively to escape detection. In the case of the men who arrived from Jeddah (and possibly elsewhere) to carry out the September 11th attack, many, if not all, used borrowed or false identities. There were at least 13 such ciphers but there could have been many more (since the only "names" of ciphers that are known are those on the four plane's manifests.) These men came, and presumably were trained and prepared, for the mission of taking over the planes and converting them into weapons of mass destruction. They were given bogus photo identifications and electronic tickets (and boarding passes) so they could board the aircraft on September 11th. Some of them used the names on the identity papers they used to get into the United States; but others of them may have used the boarding passes and photo ids of the conspirators who performed the intelligence and logistic mission. There is no reason to assume that all the conspirators were suicidists. Some of those who had the qualifications to conduct the intelligence-gathering and logistic mission might not have had the will to commit suicide. If so, they could have simply given their boarding passes to the ciphers.

Such a swap would have made room for individuals specifically trained for the assault mission and, because these ciphers had not engaged in any prior activity in the USA, made the assault teams less likely to be detected by airport security. The swap would also provide cover the escape of the intelligence-gatherers and logistic- arrangers (who would then be available for future missions.)

Consider Mohamed Atta, a well-educated architect with an advanced degree who had traveled in the United States, Europe and the Middle East. Atta had helped prepare the attack with his extensive reconnaissance, logistical and liaison work prior to September 11th and, in doing so, he left a wide paper trail booking first-class flights, attending flight schools, casing airports, purchasing flight videos, renting rooms, transferring money, renting cars and making reservations for Flight 11. Undoubtedly, after the attack, he would have been a hunted man if his name had not been on the manifest of flight 11, which took off from Boston and crashed into the World Trade Center. But was Atta on that plane?

On September 10th, Atta rented a car in Boston and drove to Portland, Maine, which is 84.6 miles from the Canadian border. The last time he was seen was at 5:58 am, standing in front of the security cameras at Portland International Airport. He had checked one bag, which included his will and videos of the flight deck of the Boeing 767. He may then have flown to Boston on a commuter flight, or someone else may have used his boarding pass on Flight 11 and he may have left the airport by plane, bus or car, for anywhere under a different identity.

Other of the known conspirators could have similarly disappeared.