General structure to allow different flight identifiers. Many identifiers can coexist.

GUFI

Globally Unique Flight Identifier. See Section 7.17

IATAFlightIdentification

Flight identification structure as defined by IATA, also known as UFI (Unique Flight Identifier). See Section 7.18

ICAOFlightIdentification

Flight identification structure based on usual ICAO fields present in the Flight Plan. See Section 7.19

IFPLIdentification

Flight identification based on a unique identifier assigned to a flight plan. See section 7.20