At the very least, 9/11 was allowed to happen, at worst, it was ordered. Think about it, what did the US gain from 9/11? “War on terror,” the Patriot Act. And from those, more power. The patriot act allows the US to spy on their citizens in a variety of ways. The “war on terror” as it is called, allowed for not only the patriot act to happen, but also to allow the rise of ISIS & other terrorist groups which would increase fear. Now tell me, how the hell was the planes not intercepted, how did they not hear about these planes being captured, surely a captain’s first instinct is to tell control they’re under attack. There’s also the case of a GPS and showing it going off course, wouldn’t it have been suspicious for a plane suddenly going off course and not hearing a response from the captain. Wouldn’t there be an air base on along the Atlantic nearby, couldn’t they intercept it? Wouldn’t they value stopping a potential attack than a single cabin?