The Court of Justice of the European Union has ruled that Irish regulators must take Dublin Airport’s 32 million passenger cap into account when allocating take off and landing slots, in a judgment that returns the long running dispute to the Irish High Court.
The ruling, delivered on Thursday 15th October, found that the cap, which stems from planning permissions granted in 2007 and 2008, is a legally binding limit on the number of passengers the airport can handle. The court said it is therefore a legitimate capacity constraint that must be considered when slots are allocated.
Background to the case
The case arose after Ryanair and Aer Lingus challenged decisions by the Irish Aviation Authority (IAA), which introduced seasonal passenger limits in 2024 so that the airport would remain within the planning restriction. The High Court referred a number of legal questions to the CJEU, which in the meantime delayed implementation of the IAA’s approach.
The cap applies to Terminals 1 and 2. Dublin Airport has already exceeded it, handling 36.4 million passengers in 2025, and is expected to pass the figure again this year.
What the court said
The judgment also addressed the position of airlines holding historic slots. The court found that carriers have no automatic right to keep or renew them, although existing operators still receive priority in allocation. In exceptional circumstances, airlines can lose slots they would otherwise retain. Historic slots were also held not to be property rights under the EU Charter of Fundamental Rights, because they are temporary in nature.
The ruling does not affect the IAA’s recent decision to make an additional 28 slots available for next summer.
Reaction
daa said the judgment brings “much needed clarity” to the regulation of aviation at the airport, and pointed to the Government’s recent legislation and its €2 billion infrastructure application as supporting future expansion.
Ryanair chief executive Michael O’Leary said the outcome underlined the need to abolish the cap, describing it as “outdated”. The airline has said the airport’s second runway can handle 60 million passengers a year, and has predicted Dublin could reach 40 million passengers next year.
Aer Lingus argued that the new airport capacity legislation has overtaken the CJEU ruling, and said it wants the remaining statutory process completed quickly.
Climate campaigners struck a different tone. Opportunity Green’s Sorcha Tunney said the ruling does not itself prevent the cap being removed, but clarifies the legal significance of capacity limits. She warned that the Government “cannot ignore the climate consequences” of removing it.
What happens next
The Dublin Airport (Passenger Capacity) Act, passed this summer, gives the Minister for Transport the power to amend or revoke the cap. daa asked for an increase to 40 million passengers in August, and Minister Darragh O’Brien has said he expects to make an order raising the limit “relatively shortly”. Environmental assessments must be completed before any order can be made.
In parallel, daa has applied to Fingal County Council for planning permission to expand the airport to 40 million passengers as part of its €2 billion infrastructure plan.
The High Court has adjourned the airlines’ challenge. Should they continue it, Irish courts will be required to apply the CJEU’s findings. The IAA is due to make its next decision on Dublin slots in April 2027, setting the terms for winter 2027/28.
