Although most U.S. airports use the same three-letter location identifier for the FAA and IATA, Wiscasset Airport is assigned IWI by the FAA and ISS by the IATA.
Most U.S. airports share the same three-letter airport codes for both the FAA and IATA, whereas Wiscasset Airport uses different codes, IWI for the FAA and ISS for the IATA.