Nonsense.
The INSTANT that passengers realized that the rules of hijacking had changed, the passengers took charge and set about stopping this nonsense.
This was even before any "enhanced security procedures".
9/11 was dependent on the free pass that had been given to hijackers in the past. That ended on 9/11.
I've made that point over and over again.
Even worse, cooperating with the hijackers was official U.S. government policy. Once we realized the stakes, We, the people, threw that idea out the window.