US airlines call for curbs on Aer Lingus over Dublin Airport passenger cap
January 8, 2026
A lobby group of US airlines has called for Aer Lingus’ access to US airports to be curtailed or suspended. The call represents the latest salvo in an ongoing dispute by carriers opposing the annual passenger cap at Dublin Airport (DUB) in the Republic of Ireland.
The calls made by Airlines for America (A4A) seek reciprocal action to be taken to restrict Aer Lingus’ traffic rights to US airports unless the Irish Government adopts emergency legislation to withdraw or suspend the passenger cap at Dublin Airport by 1st February this year.
The A4A action argues that the cap has the potential to force some US airlines to lose their existing slot rights at Dublin Airport, while also preventing other US airlines from growing their routes and traffic to the Irish capital.
US airlines object to Dublin Airport’s annual passenger cap
Dublin Airport is currently subject to a limit of handling 32 million passengers a year under a planning condition imposed by Ireland’s national independent planning body, An Bord Pleanála.
The cap was attached in 2007 to the construction of Terminal 2 at the airport and applies to both Terminals 1 and 2. It took until 2024 for traffic figures at the airport to reach the cap level, and it has been a matter of contention ever since.
The cap is adjusted between the winter and summer seasons to accommodate seasonal demand fluctuations, yet is designed to impose a hard ceiling on annual passenger figures, ostensibly to protect local residents from excessive noise pollution.
However, many airlines have called for the cap to be removed, arguing that its imposition is harmful to airport growth, is anti-competitive and is damaging to the Irish economy by restricting overseas business and tourist travel to the Irish Republic.
Aer Lingus becomes a target for US airline frustration
As reported by the Irish Independent, while Aer Lingus is not specifically identified by the A4A action, Ireland’s flag carrier is the only Irish-based airline currently serving US airports.
The carrier has been rapidly expanding its Ireland-US network since the pandemic and now serves 17 US destinations from Dublin Airport. As such, any restrictive action to be taken in response to the A4A action would potentially cause severe financial harm to the carrier.
Airlines for America (A4A) has made its formal complaint to the US Department of Transport, saying the Irish Government is restricting the number of passengers who can use Dublin Airport.
The action states that, should emergency legislation suspend the cap not be enacted by the start of February, then A4A will pursue action to restrict Aer Lingus’ access rights to continue serving US airports.
The group has previously warned that the Dublin Airport passenger cap issue could be escalated to the White House if an agreement could not be reached on the matter within the prescribed timetable.
US carriers are restricted from expanding at Dublin Airport
While US carriers such as American Airlines, Delta and United have all expanded their operations at Dublin since the pandemic, the airlines argue that their further expansion at the airport is being restricted by the passenger cap.
They also argue that, as the dominant slot holder at the airport, Aer Lingus can manipulate its slot portfolio to provide more US services at the cost of short-haul flights, giving the carrier an unfair advantage on routes across the Atlantic.
“A4A is compelled to file this complaint because Ireland continues to violate EU regulations and the United States-European Union Air Transport Agreement (US-EU ATA),” said the complaint filed by A4A.
“Specifically, the Irish Government seeks to impose a local infrastructure planning condition restricting the number of passengers at Dublin Airport to 32 million passengers per annum, which will result in the withdrawal of US carrier historical slots at Dublin Airport.”
Legal proceedings over the cap continue
In 2025, the airport’s local authority, Fingal County Council, issued an enforcement action against DAA (the operator of Dublin Airport) for breaching the cap in summer 2025. The enforcement action gave DAA two years to comply with the cap.
The cap for the peak season was set at 25.2 million seats, but it is understood to have been significantly breached. The capacity cap is now under suspension, as matters related to it have been referred to the Court of Justice of the European Union for determination over its legality.
An opinion in that case is due to be filed by one of the Court’s advocate generals in February, with the court’s final decision due to be published later in 2026.
Slot restrictions increase at Dublin as capacity grows
The Irish Aviation Authority (IAA) said it had anticipated that not all flights scheduled for summer 2025 would fit within the airport’s seat cap, even with the Slot Regulation process in place, which is designed to allocate capacity fairly and transparently based on the airport’s declared limits.
The IAA concluded that although it did not possess powers to amend or revoke planning conditions, it noted that the eradication of the 32 million capacity cap would “facilitate the continuation of all summer 2024 slot series in 2025 and also accommodate anticipated growth and new entrants in the season, including ad hoc slots.”
A4A has argued that the only reason US carriers have not yet lost their legacy slots at Dublin Airport is because of the legal action that was originally brought in the High Court of Ireland by Aer Lingus and Ryanair, which was passed to the Court of Justice of the European Union for determination.
A stay has been obtained in the action while legal proceedings continue.
All three of Ireland’s own airlines have been vociferous in their opposition to the cap at Dublin in the past. Aer Lingus, Emerald Airlines (operating as Aer Lingus regional) and Ryanair have all said that the capacity cap stifles growth and prevents Dublin from effectively competing with other European airports.
Founder and executive chairman of Emerald Airlines Pat Kenny declared the passenger cap as “Ireland’s own version of Brexit” and “the greatest act of economic self-harm since the foundation of the State”, urging the Irish government to “acknowledge the significant and far-reaching consequences of this issue”.
Featured image: Aer Lingus
