A flight from Paris to LAX would over fly ALL of the US. If the terrorist took control of the flight on the east coast they could fly the plane anywhere in the US? My guess is that the flight would cross through Canada entering the U.S. somewhere over Montanna or west of the Rockies before traveling down to L.A. Trans-continental flights follow the curvature of the globe, not the straight line lattitude path.
CNN just repeated that one of these flights was supposed to land first in Cincinnati before going on to LAX.