Thousands of people. Where do you get this crap? It would have taken a couple dozen at the most. The buildings’ owner (to bypass security) along with a small team to rig the buildings for CD. A team of a half dozen working under a construction/maintenance or asbestos abatement cover could have pulled it off at a slow pace if the CD job was spread out over months. Having worked in numerous tall buildings, I can assure you that maintenance and construction workers are always running around and nobody gives them a second glance. They could have also worked nights.

Given the compartmentalized and autocratic nature of military/intelligence operations, you would need one or two people each at a high level in NORAD/NMCC/Secret Service (to run the multiple war games we know were going on and disrupt the normal fighter response protocols), FBI and CIA (to squelch pre-9/11 investigations, which in fact is exactly what happened).

That still leaves a dozen people to manage the post-attack investigations—one or two people each in positions of operational/executive control at FEMA, the lead contractors responsible for cleanup, the 9-11 Commission (all it took was one man, Philip Zelikow, to bungle their investigation), and NIST. As far as the underlings in these organizations, most people, like you, are authoritarian personalities, so they will just unquestioningly lap up whatever they are being fed by authority figures. It’s not like some government bureaucrat or contractor dependant for their very livelihoods on staying in the good graces of the government is going to be looking to question given directives (about what to investigate and more importantly, what doesn’t need to be investigated).

As the numerous 9-11 whistleblowers that have come out will attest, not everybody is an authoritarian hand-licker and a very small minority do have some measure of integrity, so it’s not like the conspiracy was “successfully covered up” as you suggest. Sibel Edmonds for example, who had top secret clearance in the FBI and who is under two gag orders that forbid her to testify in court or mention the names of the people or the countries involved in the 9-11 conspiracy: "If they were to do real investigations we would see several significant high level criminal prosecutions in this country. And that is something that they are not going to let out. And, believe me; they will do everything to cover this up."

As far as the ability to keep things under wraps, consider the National Security Agency, which has a larger budget and more employees than the CIA. It was organized in 1949. This entire agency of the federal government remained completely hidden from the public until the 1980s, over three decades later. One of the programs run by NSA, believed to have started in the 1940s, was Project Shamrock, through which all major transatlantic telegraph cables were tapped with the cooperation of AT&T and other communications carriers. This vast program – involving people building, installing and running equipment all over the world, and yet numerous others watching and translating conversations – was kept entirely secret until the 1990s. Most American citizens have never heard of this program to this day. Other projects involving many more people than the 9-11 job would have required that were successfully kept under wraps are the Manhattan Project and the F117-A Stealth Fighter project.

The official narrative requires that only a couple of dozen poorly trained Islamic radicals deftly maneuvered through the world’s most powerful and well-funded intelligence gathering and military machine. How much easier might it have been for a similar number of people to do so, employing many unknowing others for secondary, compartmented tasks, if those handful with full knowledge of the plan also knew every aspect of the U.S. intelligence and military machine, and were in key positions governing its activities and responses?

In short, it is patently obvious that you don’t even have the beginnings of a clue what you are talking about.