Dublin Airport is facing a second day of disruption to its check-in and baggage drop in Terminal 2 after an alleged cyber attack.
A spokesperson for the airport said it is continuing to support airlines "as they deal with the ongoing disruption caused by a Europe-wide technical issue that is impacting on their check-in and boarding systems".
Graeme McQueen said some airlines in Terminal 2 are "continuing to use manual workarounds to generate bag tags and boarding passes".
"This means that the check-in and bag drop processes may take slightly longer than normal," he said.
Mr McQueen said passengers who need to check-in or drop off bags at the airport should give themselves additional time.
"Dublin Airport is expecting to operate a full schedule today, but passengers are advised to contact their airline directly for updates on their flight," he added.
London, Brussels and Berlin airports also experienced delays and disruption following the "technical issue" affecting Collins Aerospace, which works for several airlines at multiple airports across the world.
The disruption began on Friday night and continued throughout yesterday, with flights cancelled or delayed as the impacted airlines had to carry out check-in and boarding operations manually.
Passengers due to fly from the London Heathrow's Terminal 4 said they were met with queues, delays and confusion as to whether they'd be able to make their planned trips.
Heathrow said yesterday passengers should check their flight status before travelling to the west London airport.
"Collins Aerospace, which provides check-in and boarding systems for several airlines across multiple airports globally, is experiencing a technical issue that may cause delays for departing passengers," Heathrow said.
"While the provider works to resolve the problem quickly, we advise passengers to check their flight status with their airline before travelling.
"Please arrive no earlier than three hours before a long-haul flight or two hours before a domestic flight.
"Additional colleagues are available in check-in areas to assist and help minimise disruption. We apologise for any inconvenience."
It is understood British Airways at Terminal 5 remains unaffected and has been operating as normal.
Around 14 flights were cancelled and some delayed across the other terminals yesterday, although it is not clear which of these were caused by the technical issue.
Brussels Airport said: "There was a cyber attack on Friday night,19 September, against the service provider for the check-in and boarding systems affecting several European airports, including Brussels Airport.
"This means that at the moment only manual check-in and boarding is possible.
"This has a large impact on the flight schedule and will unfortunately cause delays and cancellations of flights."
The airport warned that flight disruption and cancellations would continue into today.
A statement on the Berlin Airport website said there were longer waiting times at check-in.
Collins Aerospace said yesterday it was working to resolve the issue as soon as possible.
It said: "We have become aware of a cyber-related disruption to our Muse (multi-user system environment) software in select airports.
"We are actively working to resolve the issue and restore full functionality to our customers as quickly as possible.
"The impact is limited to electronic customer check-in and baggage drop and can be mitigated with manual check-in operations."
The European Commission, which takes part in managing airspace across Europe, said it is monitoring the situation but added there were no signs the alleged cyber attack was "widespread or severe".
A spokesperson for the European Commission said yesterday evening: "The commission is closely monitoring the cyber attack that has disrupted airline check-in and boarding systems for several airlines across multiple airports globally.
"While passengers are facing disruption, aviation safety and air traffic control remain unaffected.
"The commission is working closely with EUROCONTROL, ENISA, airports and airlines to restore operations and to support passengers.
"Current signs do not indicate a widespread or severe attack."
