EU court says Dublin Airport's 32 million cap must be considered in slot allocation

The Court of Justice of the EU ruled on 15 October that Dublin Airport's 32 million passenger cap must be taken into account when allocating take-off and landing slots. The judgment in Case C-857/24 says a legally binding planning limit can count among the constraints used to assess available capacity.

The ruling does not cancel flights or order airlines to surrender slots. The Irish High Court must still apply the court's interpretation to the airlines' challenge. The immediate effect is procedural.

What the court decided

The dispute turned on whether a planning restriction could count in the assessment of available capacity, even where the airport's infrastructure could handle more passengers. The High Court referred the question to Luxembourg.

The court held that a development consent restricting operational capacity and binding the airport operator can count among the parameters for an objective analysis of capacity. It said the age of the planning rule, or changes in the policy behind it, did not make it irrelevant while it remained binding.

The outcome followed an Advocate General's opinion in February, which found that a planning limit may be taken into account when an airport with capacity problems allocates slots.

The court also addressed historic slots. Airlines that use a series regularly get priority for the equivalent season, but that priority is not an unconditional right. In exceptional cases a carrier can lose slots, or part of a series, because the legal ceiling leaves no room. Historic slots are temporary, the court added, and do not amount to a property right under the EU Charter of Fundamental Rights.

Why airlines are exposed

The Irish Aviation Authority sets seasonal capacity limits before slots are allocated. The dispute turned on whether the 32 million cap belonged in that calculation. The authority said it will consider the implications of the judgment for the domestic proceedings and for future slot decisions.

The ruling does not reverse the IAA's recent decision to allow 28 additional daily take-off and landing slots for summer 2027. Extra slots are not routes either. Airlines still have to apply and win an allocation before anything appears in a timetable.

Ryanair called the cap "outdated" and "absurd" and said the second runway gives Dublin capacity for 60 million passengers a year. Chief executive Michael O'Leary said the time for "further dither and delay" by Micheál Martin's government was over. The airport operator, daa, said the judgment "brings much-needed clarity to the various regulatory regimes impacting aviation in Ireland" and pointed to its €2 billion infrastructure application.

The numbers behind the fight

Dublin Airport handled about 36.4 million passengers in 2025, roughly 4.4 million above the 32 million cap. RTÉ reported the overshoot as about four million. The difference is rounding, not a dispute about direction.

The cap dates to planning permissions granted in 2007 and 2008 for Terminal 2 and the extension of Terminal 1. They limited the two terminals to a combined 32 million passengers a year. Enforcement has had little teeth since the High Court stayed it while the case sat in Europe.

The limit was imposed partly over concerns about road congestion around the airport. Some local residents and environmental groups still back it as a brake on a high-emission sector.

Ryanair says passenger numbers will pass 36 million this year. On 5 August, daa asked the minister to raise the limit to 40 million rather than scrap it outright. Those figures, 40 million requested, 60 million claimed and 32 million in law, frame the argument now running through the courts.

A law passed, an order not signed

The Dublin Airport (Passenger Capacity) Act 2026 commenced on 27 July. It gives the transport minister power to amend or revoke the cap after environmental assessments and a public consultation.

That is not a flick of a switch. An Coimisiún Pleanála must carry out environmental and appropriate assessments. It must then run a consultation that can last up to 28 weeks before the minister can sign any order. RTÉ's analysis of the process concluded that the cap could remain the technical legal position at Dublin well into next year.

Darragh O'Brien has said he wants the assessments done within the act's strict timelines. That would let him amend or revoke the cap as soon as possible.

What happens next

The Irish High Court must apply the CJEU's interpretation to the airlines' challenge. The Department of Transport said the minister would make no further comment because the matter is before that court.

Until an order is signed, 32 million remains the binding limit on paper, and the court has said it cannot simply be ignored.