The Eleftherios Venizelos Athens International Airport (AIA) is expected to move to IATA Level 3, the highest level of coordinated slot management, beginning with the upcoming winter scheduling season. The same regime will also apply during the 2027 summer season.
According to the Sunday edition of “To Vima”, the change is now considered necessary as steadily rising passenger traffic, the limitations of the existing aging air traffic control systems, geopolitical developments in the Middle East and the airport’s major expansion works place increasing pressure on the operation of Greece’s largest airport.
The objective of the transition to the stricter operating regime is to address the concentration of flights during peak periods—primarily early in the morning—when airlines seek to secure the most commercially attractive slots in order to facilitate connections and maximize load factors.
This practice, combined with deviations from scheduled operations throughout the day, has resulted in the chain-reaction delays recorded in recent days, affecting the entire daily flight schedule.
The issue was the focus of a high-level meeting attended by representatives of the Civil Aviation Authority (CAA), the Hellenic Civil Aviation Authority’s air navigation services, Athens International Airport, airlines and air traffic controllers. According to available information, it was the first meeting involving all stakeholders at such a senior level since 2024 devoted exclusively to summer-season delays. Participants agreed to hold a series of technical meetings to coordinate the next steps.
Athens International Airport currently operates as an IATA Level 2 airport, meaning congestion may occur during certain hours of the day, week or season. Under the current system, the National Slot Coordination Authority recommends changes to airline schedules, but those recommendations are not binding.
As a result, airlines are able to retain their original schedules even when they exceed available capacity, since the penalties currently in place are not always an effective deterrent.
Operational data illustrate the problem. Although planning assumes a capacity of 35 departures and 31 arrivals per hour, airlines in some cases schedule as many as 45 to 50 aircraft movements during the same period. One notable example occurred on June 5, when 48 departures were scheduled within a single time window, well above the airport’s operational capacity.
Disagreement Over Cause of Delays
There is, however, no consensus on what is driving the delays.
Sources at the Athens International Airport argue that the primary issue is not the total number of approved flights but the way daily air traffic planning is implemented in practice. They contend that the current system’s configuration does not allow flight flows to be adjusted to actual operating conditions during the day, preventing the airport from fully utilizing its available capacity.
According to the same sources, the hourly operational targets established by a joint ministerial decision are achieved only for a limited number of hours each week, while operational performance falls short of those targets for the remainder of the time.
Air traffic controllers, by contrast, attribute the delays mainly to the heavy concentration of flights during the morning peak. They note that when an aircraft is not ready to depart at its scheduled time—or is delayed because of earlier flights, ground handling or other operational factors—the disruption carries over into subsequent hours, creating the familiar “domino effect.”
For that reason, controllers are calling for the airport to transition to IATA Level 3, under which airport slots become legally binding and violations are subject to administrative and financial penalties.
Operational pressure is also being intensified by private aircraft, medical evacuation flights and government and diplomatic missions, which are not subject to the same slot coordination mechanism. In addition, traffic within the Athens Flight Information Region (FIR) has increased significantly, as changes to international air routes caused by developments in the Middle East have added substantial pressure to Greek airspace.
At the same time, major airport expansion works are scheduled to begin this winter, temporarily reducing available capacity because only one runway will remain operational for extended periods. Authorities are already assessing the impact on aircraft parking stands, passenger terminals, passport control facilities and baggage handling operations.
