The Irish Airline Pilots Association (Ialpa) served notice on Aer Lingus it would embark on an "indefinite" period of action, starting with a strict "work-to-rule" policy after two ballots returned successful votes for industrial action up to and including strikes.

It means from Wednesday (26 June), Ialpa’s Aer Lingus pilot members employed in Ireland will refuse to work overtime or work beyond their contracted hours.

They will also strike for eight hours on Saturday 29 June between 5am and 1pm, further compounding the impact on Aer Lingus’s flights. The airline has warned of "major disruption" to its schedule, up to 20% of which will be cancelled.

Late last week, the Irish Travel Agents’ Association (ITAA) urged Ialpa and Aer Lingus to reach a resolution, warning of "serious impact" for holidaymakers and corporate travellers.

Over the weekend, Ialpa confirmed it had agreed to restart talks with Aer Lingus. Posting to X/Twitter on Sunday (23 June), the union said: "Ialpa confirms Aer Lingus requested to resume direct negotiations this morning.

"Ialpa has indicated the association is willing to return to negotiations to try and find a resolution to the current dispute."

The dispute is over pay, with Ialpa seeking a 20%-plus pay uplift for its Aer Lingus pilot members. It previously turned down an offer worth just over 9%.

While the action is limited to Aer Lingus pilots employed in Ireland, there are knock-on effects for the airline’s operations in the UK, Europe and North America.

Aer Lingus on Sunday posted a full list of cancellations for the first five days of the action over 26-30 June, running to 221 flights, around half of which (111) are flights departing Ireland.

It has also cancelled 34 flights departing the UK – all flights to Ireland – as well as 71 departing Europe and five departing North America.

Aer Lingus’s transatlantic schedule out of Manchester is not directly affected by the action, and nor is its Aer Lingus Regional operation operated by Emerald Airlines.

The majority of cancellations – more than half (116) – fall on Saturday (29 June). In the UK, select flights departing Heathrow, Birmingham and Manchester are affected by the action.

Customers with impacted flights will be contacted directly by email and/or text message. Those who booked through travel agents will be alerted by their agent.

Aer Lingus has apologised for the likely disruption. "We fully understand the anxiety being experienced by customers given the uncertainty this has caused," it said.

"We are providing all customers with bookings within these dates the option to change flights, or request refunds or vouchers. We are also adding additional resources to help minimise any disruption."