from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. 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.
- v. To buy space on (a flight) in this way.
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. (Wiktionary)