Airlines are required by law allowing immigration and customs authorities to request access to passenger information specified in the reservation. That is why several countries, due to security reasons, have introduced the APIS (Advanced Passenger Information System) for international travelers. Passengers must provide certain information to the airline (about themselves, about the place of travel and where they stay), prior to their international journey, which then passes this information on to the authorities of the country where the APIS system applies. This also applies the transits to certain countries.
As a passenger, you must provide the required information at the time of check-in. To prevent unnecessary delays, Mainport Travel Management will put a lot of information in the reservation for you. This also will save you time and effort at your check-in.
Do you want to learn more about these safety measures? Here you can read the explanation from the European Commission.