Little was it known at the time, but 9/11 was not a normal day of blue sky aviation. On the contrary, it was one of the busiest days in the history of American aviation, a dense forest of live fly exercises, drills, simulations, fake radar injects and utter confusion. And that was before the attacks even began. This is the story of 9/11 that you didn't watch unfold on your TV that fateful day in 2001.