flynummer

Flynummer, or flight number, is the designation used to identify a specific scheduled air service. It typically consists of the two-letter IATA designator of the operating airline followed by a one- to four-digit numeric designator, for example AA 100 or AF 1234. The two-letter code identifies the carrier; the numeric portion denotes the particular service, often tied to a route and departure time on a given day or season. Flight numbers are assigned by airlines and appear in timetables, tickets, boarding passes, departure and arrival boards, and live flight information to distinguish flights on the network.

Codeshare relationships influence how flight numbers are presented. On codeshare flights, the same physical flight may carry multiple flight numbers issued by different marketing airlines; the operating airline’s number can differ from the marketing number assigned by a partner carrier. This means passengers may see different flight numbers depending on where the ticket was issued or who markets the service.

Flight numbers are subject to change due to schedule adjustments, aircraft substitutions, or route changes. They are generally reliable markers for tracking a service in bookings and on displays, but they are not a guarantee of the exact aircraft, route, or timing. In practice, numbers are reused across days or markets, especially for high-frequency or seasonal routes, while a given airline maintains consistency for a specific service as far as possible.