‒ Airplane paper ticket or e-ticket;
‒ Travel document (passport with valid visas, if applicable) or personal document (ID card).
The required documents for travelling and check-in depend on the agreement of the country issuing your passport and the country of destination. If you have a connecting flight during your travel, you need to find out whether you need a transit visa.
You can find more information about the required documents and visa requirements at your airline company or on the Ministry of Foreign Affairs of the Republic of Serbia website.