Metropolitan area airport codes
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In addition to individual-airport codes, IATA, the FAA, and various booking engines have assigned "metropolitan area codes" which represent several airports serving a metropolitan area. Not every region served with multiple airports is assigned a location identifier, however, nor are all IATA-recognized facilities necessarily included; furthermore, the inclusion or exclusion of a facility may depend on the booking system.
For example, the NYC code, representing the New York City area, includes flights to John F. Kennedy International Airport JFK, Newark Liberty International Airport EWR and LaGuardia Airport LGA. In some systems, Westchester County Airport HPN is also included; however, ZYP (New York Penn Station), ISP (Islip Airport), and JRA (West 30th Street Heliport) are generally not.