talk of code sharing when two or more airlines share a scheduled service. Each
of the airlines involved offers the flight concerned under its own flight
number, but it is operated by only one airlines. So there can be different flight
numbers for a single flight.
One example from the DUS timetable
Berlin and Etihad Airways offer a nonstop flight to New York (JFK) from
Düsseldorf on a code sharing basis. The Etihad flight number for this flight is
EY 1190, the Air Berlin flight number is AB 7450. The flight, however, is
operated by Air Berlin.
ticket shows the flight number of the airline that issued it. On the
information boards in the terminal, in the app and on the websites, all flight
numbers associated with the flight are shown on a rolling basis with the
notation “Code Sharing”.
code sharing method is mainly used within airline alliances like Star Alliance, One World or Skyteam. This allows the
airlines to offer flights that they do not operate themselves, but are operated
by a partner airline of the alliance concerned.