I didn't want to start a new thread about this, but in working on a new little project of mine I've uncovered a large amount of material that (unsurprisingly) reinforces the idea that the system could not prevent the hijackings, and that NORAD and the FAA did everything they could.
The details will be in my work when it's done, but I wanted to share a few tidbits.
-Aircraft Piracy and Terrorism are regarded as distinctly different events, and the procedure for acquiring military assistance in each case is very different.
-NORAD Active Air Defense Missions (scrambles to intercept unknown aircraft entering the ADIZ from overseas) are distinctly different to FAA requests for escort fighters.
-NORAD did not scramble alert fighters to intercept Payne Stewart's learjet - all of the fighters that shadowed his aircraft were unarmed and the Air Force unequivocally stated at the time that they absolutely did not even consider the possibility of shooting the aircraft down - even if it crashed into a heavily populated area.
-Fighters were scrambled from an air base that had armed alert fighters, but the alert fighters were not used.
-Before the Payne Stewart incident, there were two other similar incidents that resulted in interception. The first, in 1980 involved the interception of a Cessna 441. When ANG fighters eventually reached the aircraft it was over 1,000 miles off course - a distance that would take the Cessna 441 at least 3 hours to cover. The second was a 1988 incident which was intercepted by a fighter trainer pilot that was already in the air at the time.
-Escort fighters for a hijacking could only be requested by the FAA Hijack Coordinator, and had to be approved by the Secretary of Defense.
-The only way around this was for NORAD to declare an Active Air Defense Mission, however NORAD regulations did not allow an AADM over continental US airspace.
Anyway. Just a handful of interesting facts.