| Type | FlightNumberType | 
|---|---|
| Description | Identifies a flight number (1 to 4 numbers) or OPEN or ARNK. | 
| Comments | OPEN - Used in lieu of a flight number when a specific flight number is unknown but service is present. ARNK - Used in lieu of a flight number when surface transportation is used when there is a break in the continuity of the flight itinerary. | 
| XML type | xs:string | 
| AIDX XSD | IATA_SimpleTypes.xsd |