Wanderlust World Wanderlust World With both code-share and interline agreements, a flight can have flight numbers other than the one assigned by the primary airline. A code-share flight operated by a given airline from one destination to another has a different flight number for each airline with passengers on the flight. Interline agreements use the same flight number for each segment of a multiple-leg trip between destinations. An interline agreement usually applies the same flight information from the first part of the flight to each part of the trip.
Code-share flights allow you to accumulate frequent flyer miles because the single-segment flight operates as the same airline you have a frequent flyer agreement with, and airlines often have alliances for code-share flights. Interline agreements usually do not offer frequent flyer miles for parts of the flight not operated by your primary airline. Check with your airline for agreement information specific to your flight.
When you board an interline flight, all of your checked baggage follows you through the different segments to your final destination. If you board multiple code-share flights, you might need to re-check your baggage because the airlines process code-shares as separate flights.