Sometimes you will be boarded on aircraft that do not belong to the airline you have contracted. This is due to different commercial agreements between airlines or for technical reasons.
It is normal for air services to be carried out through joint operating agreements between several airlines. This is called Code Sharing. This modality of agreement between companies allows a better use of the capacity of the airplanes and, therefore, the reduction of air fares provides better opportunities to travel to any destination and makes it easier for passengers to make connections on flights with intermediate stopovers.
At the time of purchasing your ticket, the contracted company must inform you of the Identity of the company that will operate your flight. In the event of a change of operating carrier, you will be informed prior to boarding.
Respective Responsibilities of the Contracting Carrier and the Actual Carrier
The Montreal Convention provides that the contracting carrier is subject to the provisions of the convention in respect of all carriage under the contract and the actual carrier only in respect of the carriage it performs.