Greece's Aegean Airlines will continue to strengthen its network in the former Yugoslavia this winter season, with services to Dubrovnik to operate for the majority of the season, while both Belgrade and Zagreb will see additional flights. The carrier's seasonal service between Athens and Dubrovnik will be extended for most of the winter, with flights to be maintained twice per week up until January 4. Services will then resume at the start of the 2020 summer season in late March of next year. Aegean introduced operations to Dubrovnik in the summer of 2015 and has since maintained the route exclusively on a seasonal basis.

During the upcoming winter season, Aegean will add an extra weekly flight on its service to Zagreb for a total of three. The new rotation will be introduced on Thursdays and will operate on and off throughout the winter. Overall, the Zagreb route, which was launched only last year, will be maintained until January 15, before it goes on a month-long hiatus, and resumes on February 24. Aegean faces no direct competition on its operations to Croatia during the winter. Flights to both Zagreb and Dubrovnik will be run by the airline's regional subsidiary Olympic Air and its 78-seat Bombardier Dash 8 turboprop aircraft.

The Greek carrier will also increase its operations between Athens and Belgrade this coming winter season. It will maintain five weekly flights between the two capital cities, up from three last year. As a result, it will retain its summer frequencies over the winter months. The route will be operated by the Airbus A319 aircraft between Monday and Thursday and the A320 on Fridays. Aegean Airlines codeshares on the service with Air Serbia, which itself plans to maintain daily flights between the two cities during the 2019/20 winter season. The Greek and Serbian national carriers have also expanded their wide-ranging codeshare partnership this summer, with Aegean recently placing its flight number and designator code onto its counterpart's newly launched service between Belgrade and Rijeka.