— 纸包不住火. A coordinated attack involving 4 civilian passenger flights involve lots of planning, resources, funding. Such a large scale operation could involve dozens of individuals.

Suppose there are 20 suicide hijackers. They need to somehow say goodbye to loved ones before they go on the mission. Their families also have a big need to understand why and how they died.

If it had been a U.S. government project, then over 20 years someone would have leaked a smoking gun evidence, blew a whistle. Press freedom — U.S. mainstream media have freedom to report on any of these “discoveries”.

Many non-mainstream media did report such discovereis, but not convincingly, including films.

— sacrifice and justification .. the people involved need to be fully convinced, as the project is designed to “sacrifice” thousands of civilians. How do you brainwash so many team members?

— Demand for justice by the families of operatives.. If it had been a U.S. government operation, then some of the hijackers’ family members would have felt their loved ones (the hijackers) died for an unjust cause.

Arab families may not say “unjust”, but in this conspiracy theory, we are talking about American soldiers hijacking American civilian flights killing ordinary New Yorkers, not politicians.