The hijackers’ training records from several U.S. flight schools indicate that they were marginal pilots, at best, even in single-engine airplanes. In early 2000, three of the pilot/hijackers are heavily documented at a small flight school near Venice, Florida, while the fourth attended schools in Arizona and California. This would account for the basic flight training of the pilots but in no way can explain the expert level of airmanship required for the 911 hit.

Dozens of reports focused on the pilot/hijackers Mohamed Atta, Hani Hanjour, Ziad Jarrah and Marwan al-Shehhi. Flight instructors around the United States told similar stories of attempting to train them. All four had a very difficult time in their basic training on small, single-engine airplanes. The English-speaking instructors repeatedly cited the language barrier with the Arabic-speaking students as a major obstacle and said that they had encouraged the students to quit. Obviously, this language issue had found a solution by 911; the only logical solution is that Arabic-speaking flight instructors were used, more specifically, Arabic-speaking Boeing flight instructors.

By using small flight schools for basic flight training, the cell remained below the radar, while the pilots’ documented use of the schools could be counted on later to provide some sort of explanation (albeit a very weak one) as to how they learned to fly these complicated heavy jets, and might help keep investigators off the trail of the real training. But the leap from a small 4,000-pound single-engine propeller airplane to a 300,000-pound twin-engine jetliner needs a specific explanation. For instance, it took me 20 years, dozens of ground school courses and 15,000 hours between my first lesson and taking command of my first commercial airliner. Adding computer games and outdated simulators to their training was a helpful step, but until they actually felt the yoke and added the hours of experience it takes to understand the momentum of a heavy 767, they would be all over the sky and completely out of control. Not only were they under control, they flew above the average skills required to operate in an airline environment. This miraculous leap has only one explanation: expert and repeated training in the actual Boeing 757 or 767. And by all indications, this took place in the final months of preparation, during the spring and summer of 2001.

There are two different worlds in aviation — the general single-engine airplane world with a service ceiling of 10,000 feet and a top speed of around 200 miles per hour, and the commercial swept-wing jetliner world at 40,000 feet and Mach numbers for speed calculations. Little within that first world prepares the pilot for the second, high-altitude world.

So began my search for Middle Eastern operators of Boeing airliners. Because the hijackers were mostly Saudi Arabian, the firm of Dallah Avco, a Saudi operator of multiple private Boeing airliners, soon stood out as a focal point. To my amazement, I immediately discovered that Congressional investigators had already linked Dallah Avco with the actual hijackers. Omar Bayoumi, a Dallah employee and operative within the Saudi Ministry of Aviation, had provided housing and basic support for three hijackers: Nawaf al-Hazmi, Khalid al-Mihdhar and the pilot/hijacker of American 77, Hani Hanjour.

FBI evidence of the cell would confirm that the hijacking team of American 77 had formed and operated separately with direct financial support from top-level members of the Saudi government, bitter enemies of al Qaeda. The picture was beginning to clear.

From this point in the research, the guilt needle began pointing steadily toward Saudi Arabia, in part because 15 of the 19 hijackers were Saudis. With every new piece of evidence, that needle does not fluctuate. As the focus narrowed on San Diego, the footprints of a large Saudi contingent began to appear. Congressional investigators had found, within buried FBI files, evidence that United States Senators would later call “undeniable” that top Saudi officials had known that terrorists were entering the U.S. beginning in 2000 in preparation for some sort of attack. These same officials are among those who work with American oil companies and regulate the flow of crude oil to the United States, the same Saudi officials that regulate the price that has gone from $30 per barrel to over $140 post 911.

One Saudi official in particular, Prince Bandar bin Sultan, Saudi Ambassador to the United States from 1983 to 2005, was quickly traced to direct funding of the hijackers, through cashier’s checks, not from him he would say, but from his wife. Alabama Senator Richard Shelby, Maine Senator Susan Collins and Florida Senator Bob Graham learned that Saudi officials had directed agents in the United States to assist the future hijackers. These senators would quietly back out of the investigation after the White House threatened them with “leaking classified information” and a criminal probe. Senator Graham was told in no uncertain terms to back off and shut up in telephone calls from Vice President Cheney. This evidence alone on the Saudis provided more plausibility than two chapters of KSM’s ramblings. Here was opportunity to provide airplanes and instructors for hijackers who were solidly linked to Saudi operatives working for Prince Bandar.

Something about this jogged my memory. In the spring and summer of 2001, I had noticed an odd airplane frequently parked on the corporate ramp at Lindbergh Field in San Diego. My schedule in 2001 was heavy with San Diego trips and I became curious about the highly unusual airplane with its tail number registration HZ-124. The heavy four-engine Airbus A340, normally configured for 400 seats and painted with airline livery, was unmarked and painted like a private jet. A search of the tail number disclosed that the owner was Prince Bandar bin Sultan, Saudi Arabia’s Ambassador to the U.S.

The Saudi aviation presence in San Diego was part of the puzzle. Dallah Avco could easily provide the Boeings, simulators, instructors and all the required training needed to explain the hijacker’s flying proficiency. The remaining mystery was where the training took place.

As I read through the 911 Commission’s report, I noticed that something had drawn all the hijackers out west on several occasions. The 911 Commission reported that each pilot/hijacker had made multiple trips to Las Vegas in the spring and summer of 2001; the commission had “no explanation” for this destination. But, logically, the vast Mojave and Sonoran Deserts would be the perfect training ground for practicing a high-to-low-altitude, coordinated attack.

Initially, I focused on the many airline storage airports scattered throughout the southwestern deserts, where various airliners come and go without drawing much attention. Major airlines operate leased aircraft owned by investment banks. As an airline’s fleet requirements change, planes are routinely parked while new lease agreements are negotiated. The dry desert preserves the planes’ avionics and interiors while they sit, sometimes for years at a stretch. As I conducted a search throughout the deserts using Google Earth, one airport north of Tucson began to stick out.

At the same time, from several old Iran-Contra sources I began hearing about a hush-hush airport used by the government contractor and mercenary outfit Blackwater, to train covert, special operations flight crews. I soon learned that major flight training had been conducted in the middle of the night with military and civilian airplanes in top-secret fashion. Blackwater is one of several operators that use the very airport I had run across — Pinal Airpark, a secluded desert facility near the town of Marana, Arizona, and near the former home of Saudi Arabian pilot Hani Hanjour, the hijacker pilot of American 77. I discovered that over 80 perfectly airworthy commercial airliners are scattered around the airport and heavily guarded by a mercenary army with covert Saudi ties. The opportunities are perfect to “borrow” a Boeing for unlimited and undocumented air training in the dedicated practice range over the desert. The means and the opportunity to slip hijackers in for training were all in place.

Investigative author Jeremy Scahill had also discovered Pinal and written extensively about it in his 2007 book Blackwater: The Rise of the World’s Most Powerful Mercenary Army. He traced Pinal’s four-decade history of clandestine paramilitary activity, from Vietnam and the famous opium cargo outfit dubbed Air America to today’s government contracts in the “War on Terror,” such as the so-called Torture Taxi flights to U.S.-run detention facilities in Afghanistan. Scahill reports that these untraceable contracts govern operation of Blackwater’s fleet of Casa 212 cargo planes that frequent Pinal. He reports that Blackwater’s president Gary Jackson has been bold in bragging that Blackwater’s “black” contracts are so secret, he could not tell one federal agency about Blackwater’s work with another.

“Air Blackwater,” previously known as Aviation Worldwide Services, formed in early 2001, just when the 911 hijackers were in the final stages of training. Public statements said they were to provide “military training operations and aviation transport” for the U.S. government. AWS was then acquired by Blackwater in 2003, as the Iraqi occupation was getting under way. Gary Jackson announced that the new aviation department “complements our strategic goal of providing a ‘one stop’ solution for all of our customer’s security and tactical training needs.” “Tactical training,” of course, raises a red flag. Evergreen International, an aviation company whose board includes the former head of the CIA’s air operations, has taken over management of Pinal while the government doles out no-bid, untraceable “black” contracts to Blackwater, Aero Contractors, International Air Response, Evergreen, SA Incorporated and a host of others.