The IAA is responsible for enforcing the EU Airport Slot Regulation, which ensures that, where airport capacity is limited, the maximum available capacity is efficiently identified and distributed fairly through the allocation of take-off and landing slots by an independent coordinator.

Capacity is managed down to intervals as short as 10 minutes to optimize usage.

The IAA’s role involves determining Dublin Airport’s capacity and setting guidelines for slot allocation, while considering various technical, operational, and environmental factors. These include runway and airspace capacity, aircraft stand availability, passenger processes like check-in and security, and planning conditions set by the authorities.

The proposed seat limit aligns with Dublin Airport operator daa’s recommendations during coordination committee discussions, where daa also emphasized the importance of considering these conditions.

The coordination committee, which includes Dublin Airport and the airlines operating there, advises the IAA on capacity matters under the Slot Regulation.

The Summer 2025 season would be the second scheduling period to factor in a seat cap corresponding to 32 million passengers annually. For Winter 2024 (October 26th, 2024, to March 29th, 2025), the seat cap is set at 14.4 million.

Overall, the proposed capacity for both seasons would be 39.6 million seats. The seat cap exceeds the passenger cap due to considerations of expected load factors (the percentage of seats filled on each flight) and adjustments for transfer passengers.

The IAA expects that demand for slots in Summer 2025 will greatly exceed the proposed seat limit. As with Winter 2024, there may be little to no additional capacity for new or ad hoc slot requests for passenger flights at either Terminal 1 or Terminal 2 during this period, largely due to planning restrictions. This situation will affect airlines, Dublin Airport, and the traveling public.