That was 13 years ago, and since then the practice has improved even more. This year just this year, we`ve seen a few crazy codeshare agreements, for example: interline agreements are the most basic types of agreements you can have between airlines. An interline agreement is simply a commercial agreement between airlines to treat passengers when they travel with multiple airlines on the same route. This allows passengers to check their luggage to their final destination, check in to their destination, possibly be re-routed to another airline in case of irregular operation, etc. In the case of the “block”, each of the companies sells part of the available seats, according to a distribution agreed in advance by contract between the partners, which can also be defined as the chartering of part of the airline of the operating company by its partner. In the case of “Sell and Report”, each company has access to all aircraft seats and can sell them on its own terms (within the framework of the commercial policy agreements agreed between the partners). For the passenger, this practice has the advantage of increasing the frequency of available flights, but contributes to price confusion, since participating airlines may offer different fares for the same service. This practice has become common in alliances like SkyTeam, including for local flights – for example, Aeromexico can sell flights between Nice and Paris with the Air France shuttle. Note, however, that this example is only possible in the pursuit of a flight to a destination for which Aeromexico has traffic rights, for example a Paris-Mexico. The exact operation of this revenue participation agreement depends on the specific agreement, but the idea is that two airlines essentially act as one in a joint venture. You`ll know if your flight will be part of a codeshare, as it will be displayed in Alternative Airlines` search results as “Executed by”. Below is an example of a codeshare agreement, a finnAir flight operated by British Airways and an American Airlines flight operated by British Airways…