On 12 February 2026, Advocate General Campos Sánchez-Bordona issued his Opinion in C-857/24 daa and Others.

The Opinion arises from a preliminary ruling request by the Irish High Court (Court) in proceedings brought by Aer Lingus Limited, Ryanair DAC, JetBlue Airways Corporation and United Airlines Inc.. The airlines challenged the Irish Aviation Authority’s (IAA) determination of coordination parameters for Dublin Airport for the Winter 2024/25 and Summer 2025 seasons, under Regulation (EEC) No. 95/93 (Slot Regulation).

Background

Dublin Airport has been a coordinated airport, meaning an airport where, since 2007, to land or take off, an air carrier or operator must have been allocated a slot by a coordinator, subject to exceptions.

On 29 August 2007 and 10 January 2008, An Bord Pleanála, as it then was, granted permission for the construction of Phase 1 of Terminal 2 and the Terminal 1 extension respectively. The permission was conditional on the combined capacity of Terminal 2 and Terminal 1 not exceeding 32 million passengers per annum, unless otherwise authorised (32 mppa condition, the passenger cap). The basis for this decision was to promote balanced development between the eastern campus and the proposed western campus, given transport capacity constraints at the eastern campus. At that time, the airport’s overall capacity was estimated at around 45 million passengers per year.

On 7 May 2024 and 10 October 2024, the IAA published its Final Decision on Winter 2024 and Summer 2025 Coordination Parameters at Dublin Airport (Decisions). The latter included a condition in the form of a seasonal seat cap, which meant the airport coordinator was unable to accommodate all slot requests from air carriers or allocate certain historical slots.

The Dublin Airport managing body and a number of airlines challenged the Decisions before the Court. The Court provisionally suspended implementation of the Summer Decision and referred three questions to the European Court of Justice (CJEU) for a preliminary ruling, asking in essence:

• Whether the coordination parameters for the allocation of slots may reflect conditions imposed by the planning authority, specifically an annual passenger cap; whether the 32 mppa condition qualifies as a relevant technical, operational or environmental constraint for the purposes of setting coordination parameters; and whether that constraint forms part of the objective analysis of the capacity at the airport,

• If the 32 mppa condition is a ‘relevant constraint’, whether it is permissible to withhold from air carriers a number of series of historical slots to which they would otherwise be entitled under the Slot Regulation, and

• If, in answering the first two questions, the following arises for consideration, whether the Slot Regulation prohibits airport management from deciding to close the airport for a period of time to prevent slots from being used to avoid a breach of an annual limit of passengers.

The Opinion

Advocate General Campos Sánchez-Bordona found:

• ‘Operating Constraint’: The process of allocating slots at a coordinated airport must be carried out with an assessment of all the relevant technical, operational and environmental factors affecting airport capacity. These factors are not only physical or material, but also include legal constraints which directly or indirectly affect the use of the airport. Compliance with the 32 mppa condition can be classified as an ‘operating constraint’, regardless of whether a planning authority imposed it. What matters is that it restricts the airport’s ‘operational capacity’, making it a relevant factor in objectively assessing the volume of air traffic the airport can handle.

• Historical Slots: These should not be understood as property rights - that interpretation poses “serious difficulties”. Slot allocations are “mere rights of use” granted by the competent authority in connection with specific airport infrastructure and are subject to that authority’s future decisions. Removing or reducing slots to comply with the airport’s capacity does not interfere with the freedom to conduct business.

• Closure of the Airport: the question referred is ‘inadmissible’; there is nothing to suggest that the airport operator ordered, or planned to order, the closure of that airport to avoid breaching the 32 mppa condition. The Slot Regulation already contains mechanisms which avoid measures as extreme as closing an airport to comply with a limit that has been known well in advance. A decision of that kind by the airport operator would be “difficult to imagine”.

The Passenger Cap - A Roadmap to Removal

On the same day as the delivery of the Opinion, the Department of Transport published the General Scheme for the Dublin Airport (Passenger Capacity) Bill 2026 (the Bill). In line with the commitment made in the 2025 Programme for Government to work with stakeholders to lift the passenger cap, the Bill empowers the Minister for Transport to amend or revoke a planning condition that limits passenger capacity at Dublin Airport.

Speaking at William Fry’s Energy & Infrastructure Summit, Minister O’Brien stated he hoped to see legislation passed through the Houses of the Oireachtas by summer recess.

The decision to remove the passenger cap has been welcomed by the Dublin Airport Authority, which stated, “together with daa’s €2bn plan to future-proof Dublin Airport’s infrastructure, the move to remove the outdated cap artificially restricting growth at Dublin Airport is good news for Ireland.”

The Opinion is not binding on the CJEU, which will deliver its judgment in due course.