codeshare

code +‎ share, because of the change in the flight's two-letter airline identity code. One aircraft will have two or more codes and flight numbers.

codeshare (plural codeshares)

1. (aviation) An agreement whereby an airline buys space on another airline and markets the extra space as its own. Often used to increase a route network without the costs of running a full service.

codeshare (third-person singular simple present codeshares, present participle codesharing, simple past and past participle codeshared)

1. (aviation, transitive, intransitive) To buy space on (a flight) in this way.

• deroaches