Passenger security screening, already required prior to deregulation, needed to be re-worked
to avoid having connecting passengers go through screening again at a hub. An example of this
was Dallas/Fort Worth International Airport (DFW). As American Airlines built its hub, the
terminals, which were originally conceived as an origin and destination (O&D) “drive to gate”
concept, required a major internal reconfiguration to provide a continuous secure corridor along
its linear gate configuration