Between 1991 and 2001: NORAD Exercise Simulates Crash into Famous US Building

At some point between 1991 and 2001, a regional NORAD sector holds an exercise simulating a foreign hijacked airliner crashing into a prominent building in the United States, the identity of which is classified. According to military officials, the building is not the World Trade Center or the Pentagon. The exercise involves some flying of military aircraft, plus a “command post exercise” where communication procedures are rehearsed in an office environment. [CNN, 4/19/2004]