Aer Lingus issued an apology for “severe disruption” after more than 50 flights were cancelled due to a check-in systems glitch.
The Irish carrier axed 51 flights mainly between Dublin, the UK and other European destinations on Saturday afternoon.
Large queues developed at Dublin airport due to the fault while long-haul services from the Irish capital faced delays and reduced capacity due to security restrictions being imposed due to the systems outage. Services by Aer Lingus Regional, operated by Emerald Airlines, faced delays. Transatlantic flights from Shannon operated as normal, according to Aer Lingus.
Dublin airport warned passengers due to fly on cancelled services not to travel to the airport on Saturday. Queues also developed at Heathrow Terminal 2 for passengers trying to check in for Are Lingus flights.
Extra staff were deployed in Dublin as the airline returned a to a full schedule on Sunday.
The carrier said: “Aer Lingus sincerely apologises to customers for the severe disruption and inconvenience caused by the unavailability of key systems for check-in, boarding and our website.
“This system outage was caused by a break in connectivity in services from a UK network provider.”
The carrier added that any passengers affected by Saturday’s disruptions will be able to apply for a refund or change their travel plans free of charge.
“As systems have now been restored we are contacting customers directly in order to re-accommodate them as efficiently and possible.
“We have made additional customer service agents available to deal with high call volumes – please bear with us as we try to service all our customer queries.
“We will also share information regarding customers’ rights and the airline’s obligations under Regulations (EC) 261/2004.”
Which? consumer law expert Lisa Webb, said: “Aer Lingus’ sudden cancellations of flights to and from the UK and Europe will cause thousands of passengers distress and anxiety when it comes to their travel plans.
“In events such as these, airlines should be offering the option of a refund or to reroute passengers on any reasonable route as quickly as possible, using other airlines where necessary.
“Aer Lingus must also give clear information to affected customers about their entitlement to compensation.”