Dianavan,

Explain your "undetected" comment. The planes were watched from the time their erratic flight paths began until they were so low that radar could not follow them. The transponders were turned off, so the air traffic controllers did not know their altitude, but they could estimate their groundspeed and knew their flight direction. Once they determined that a hijack situation was unfolding most controllers thought the planes were headed for Cuba - their intial turns were to the south.

An F-15 was scrambled from an air base to intercept the second of the two jets that hit the towers, but it arrived mere minutes after the jet hit the building. What is still unclear is what they would have done if they had arrived before the jet hit the tower. The "shoot" order had not been issued at that time. The jets scrambled to intercept the jet that ultimately went down in PA probably would have been given "shoot" orders, but there is even some doubt that they would have made it to DC before the jet hit the White House.

All four jets were watched until seconds before they were destroyed. What exactly do you mean by "undetected?"

Freightdawg

(by the way, I was one of the many thousands of other pilots that were flying that day. I will never get the chill out of my bones that occured when I heard the order that all planes were to land asap regardless of origin or destination. It was clear. Land now. Shut up and ask your questions on the ground. The controllers managed to do the most incredible, professional and almost impossible job imaginable without one mishap. Their accomplishment on that day is the stuff of true heroism. Their story needs to be told as much as any of the "first responders" on that horrible and bleak day.)