I suspect this was the whole motive behind 9/11. Terrible as that was the effects go much deeper. I really don't think the people behind it expected the destruction to be as complete as it turned out & this must have exceeded their wildest dreams. The immediate effect on the airline industry was disastrous but although some companies fell by the wayside it was starting to recover. Recent events have combined to make its long-term survival much worse. I'm not exaggerating when I say that playing the game the way these people planned is the most serious threat I've seen to our way of life during my lifetime.
I think it turned out just as planned. Bin Laden as an Engineering degree so he knew that the two towers were going to fall down. Remember, it wasn't the first time he tried to knock them down.