Aer Lingus says flights are back to normal today, after chaos at Dublin Airport on Saturday.
It cancelled 51 flights that day, mainly between Dublin Airport, Europe and the UK, leaving many passengers stranded.
It later fixed the technical hitch, but thousands of passengers were affected, and they will want to know how they can be compensated.
Irish Times consumer affairs correspondent, Conor Pope, has this advice for customers on what they're entitled to.
"In the first instance the passengers need to maintain a direct line of contact with the airline.
"If they are unhappy with the decisions taken by the airline, when it comes to compensation, when it comes to proper redress for the cancelled flights, people then need to contact the Commission for Aviation Regulation.
"That's the ultimate arbiter for what happens next."
