While you may not have known, you’ve almost certainly been on a flight that’s in codeshare, and you’ve probably bought a ticket that might not have been possible to buy if the codeshare contracts do not exist.
Each commercial flight has its own label consisting of two letters of the airline (IATA code for Croatia Airlines is OU) and certain numbers. Eg. The designation of one of Croatia Airlines' flights on the Zagreb - Dubrovnik route is OU664, where OU stands for Croatia Airlines, and 664 is the number of the flight. By a simple search on the Internet, if you enter the above, you will get the information that this is a flight of the mentioned airline from Zagreb to Dubrovnik.
Likewise, when you arrive at any airport in the world and look at the large screens on which are announced arrival and departure flights, you will see that the signs and numbers are changing. Why? Precisely because of the codeshare agreements between the airlines. For example, Croatia Airlines flight from Zagreb to Frankfurt is marked as OU416, but it will also be marked as UA7269, LH6002 and OZ9374. UA stands for United Airlines, LH for Lufthansa, while OZ is code of Asiana Airlines. Does this mean that three planes take off from Zagreb for Frankfurt at the same time? No, there is only one flight and it will be operated by Croatia Airlines. Due to the signed codeshare agreement between Croatia Airlines, Lufthansa, United and Asiana, their codes for that flight will also be shown. So, there is only one flight, and it is performed by one of the companies listed, in this case the Croatian national airline.
Coming to the key part, what is a codeshare flight? A codeshare flight is a commercial flight operated by one company and advertised and sold on the market by other airlines. The codeshare agreement actually allows you to buy one ticket from Zagreb to New York, via Frankfurt, with United Airlines, although this American company does not fly to Zagreb and on the Zagreb - Frankfurt route you will use the service of Croatia Airlines. This agreement allows you to buy a ticket to Seoul on Asiana Airlines website. First flight will be operated by another airline. Lufthansa is also flying to Zagreb, but in order to give its passengers more choices, it is in codeshare with Croatia Airlines on this route. Companies generally have codeshare contracts with airlines within the same alliance.
If you look for a ticket from Zagreb to New York on the United Airlines website, United will offer you one ticket with two flights (one transfer), in this case in Munich. The first flight will be operated by Croatia Airlines, while the second flight will be operated by United Airlines, under the details of the route you have stated that the operator of the first flight is Croatia Airlines. So the flight from Zagreb to Munich will also have the United Airlines code.
The same goes for Asiana Airlines, if you want to buy a ticket from Zagreb to Seoul on their website, you will be shown the following:
So, the first flight (Zagreb - Frankfurt) will be operated by Lufthansa, and then in Frankfurt you will go on an Asiana flight to Seoul.
There are various options, for example, on the website of Croatia Airlines you can buy a ticket to Munich, on the web it will be displayed as follows:
In this case, on the official website of Croatia Airlines, you bought a Lufthansa ticket on the Zagreb - Munich route, which will be operated by a Germanwings aircraft leased by Lufthansa. So, a ticket bought from one airline, the flight of another, and the plane of a third company.
There are two important terms in aviation related to the codeshare agreements. Operating carrier is a term used in the airline industry for an airline that operates a flight, while marketing carrier is a term used for a company that has nothing to do with the flight itself in operational terms, but advertises and sells it.
There are several different versions of the codeshare contract that airlines use:
1.) Block space codeshare: in this case the marketing carrier buys a certain number of seats on each flight from the operating carrier. A company that buys seats in this way generally pays a fixed price, and a company that operates a flight cannot sell seats that it has sold to another. This principle of codeshare contract is less common than other types of contracts, but it is also used nowadays.
2.) Free flow codeshare: the systems of the two airlines exchange data in real time through different systems. All classes are available for sale at both airlines and any company can sell as many seats as it wants on a every flight.
3.) Capped free flow: almost the same as the previous type, but there is a maximum number of seats that a marketing carrier can sell per flight.
Remember, when you buy your ticket it will state who is performing the flight. At the time of purchase, all airlines offer information such as aircraft type on the route, the duration of the flight, as well as which company operates the flight itself (listed under Operated by).
The only thing that matters to you is that you have your confirmed ticket and that you know which company you are traveling with so that you don't accidentally get confused at the airport and wait for a call for boarding at the wrong gate. We do not write this to you for no reason, we know that it happens almost on a daily basis and when it happens - it's your own fault. Most likely, you will have to buy a new ticket. Of course, the company listed everything in the Terms of Purchase that you accepted, but probably did not read. This is the worst possible way to miss a flight and lose money, all due to lack of information.
As many Croatian citizens live and work abroad, many of them buy airline tickets for their parents to bring them for a visit. Passengers who are not familiar to travel by plane and don't know how the airport runs in general, find it very difficult to cope in such situations and often have failures like this one, so it is very important to inform people for which you buy a ticket about all important details, and if the flight is codeshare - consider this information essential.
To avoid such cases in the future, as well as all the other embarrassing situations that a missed flight brings, we hope that this article will give you a basic knowledge of codeshare flights.