CJEU Confirms Dublin Airport Passenger Cap Must Be Considered When Allocating Slots

Key Takeaway: The Court of Justice of the European Union (the "CJEU") today confirmed that planning conditions, including Dublin Airport's long-contested 32 million passenger Cap (the “Passenger Cap”), must be taken into account when setting the airport’s operating capacity.

The judgment arises from a series of proceedings concerning the interaction between the Passenger Cap imposed under Dublin Airport's planning permissions and the EU regulatory framework governing slot allocation at European airports.

What is the background to this judgment?

Planning permission for the extension of Terminal 1 and the construction of Terminal 2 was granted in 2007 and 2008, subject to a condition that annual passenger throughput at Dublin Airport would not exceed 32 million passengers.

Importantly, the combined physical capacity of Terminal 1 and Terminal 2 exceeds 32 million passengers. The Passenger Cap has, therefore, functioned as a regulatory constraint rather than a reflection of the airport's structural capacity.

In 2024, the Irish Aviation Authority (the "IAA") set operating capacity for Dublin Airport, which reflected the Passenger Cap and restricted activity to levels below projected passenger demand. That decision was challenged by DAA PLC, a number of airlines and several industry stakeholders.

The resulting proceedings came before the High Court, where a key issue under consideration was whether EU law permits the IAA to take the Passenger Cap into account when setting operating capacity. The High Court decided to refer the issue to the CJEU.

Earlier this year, the Advocate General (the “AG”) issued an opinion concluding that the IAA was entitled to take the Cap into account when exercising its powers under the applicable EU legislation.

What has the CJEU decided?

The CJEU decision, which issued today 15 October 2026, has now largely endorsed the AG’s opinion. The CJEU held that planning conditions contained in development consents may constitute relevant operational constraints which the competent authority and airport coordinators are entitled, and in some circumstances required, to consider when setting operating capacity.

The CJEU also emphasised that it is immaterial whether a planning restriction is longstanding or whether the policy rationale underpinning it has subsequently evolved. The key consideration is whether the restriction remains legally binding and affects the airport’s operating capacity.

The judgment confirms that airport slots may be restricted where necessary to ensure compliance with applicable planning conditions, even where those restrictions result in available demand exceeding allocated capacity.

The CJEU also rejected arguments that airlines possess vested property rights in airport slots. While EU law provides certain protections for airlines which have historically utilised a series of slots, the continued allocation of those slots remains contingent upon the airport's available capacity and operational constraints.

What impact will the CJEU’s judgment have?

Notwithstanding the significance of the CJEU's ruling, its practical consequences may ultimately be limited. Since the reference was made, the Oireachtas enacted the Dublin Airport (Passenger Capacity) Act 2026 (the “Act”), which was signed into law earlier this year. The Act empowers the Minister for Transport (the “Minister”) to amend or remove the Passenger Cap through a new statutory mechanism.

As a result, the legal framework governing passenger capacity at Dublin Airport has changed significantly since the proceedings were commenced. With the Minister expected to exercise those powers, the long-running dispute concerning the original Passenger Cap may soon become largely academic, regardless of the CJEU's important clarification of the applicable EU law position.

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