Poor weather and a busy holiday flights schedule caused long delays at Dublin Airport yesterday.
A spokeswoman for Aer Rianta said delays averaging between half an hour and an hour were experienced by many, "but not all", passengers.
Low visibility procedures had to be put in place from 11 a.m. onwards due to heavy fog at the airport. The procedures meant an increase in taxying-time for aircraft, and a lengthening of the gap between take-offs and landings.
"The fog was very bad all day," the spokeswoman said. "Low visibility tends to slow down operations a bit. Also, some inbound flights were delayed due to late take-offs on the other side."
Aer Lingus and Ryanair also blamed poor weather conditions for the delays.
A spokeswoman for the former said there were also long "but not exorbitant" delays at check-in desks due to the large number of charter and holiday flights.
"Everyone is travelling with baggage, either for skiing or sun holidays. We don't have the high number of hand-luggage travellers that we would normally have. As a result, it is taking up to two hours to check people in," she said.
"The flights are chock-a-block. There is huge traffic through the airport and we can only advise passengers to give plenty of time before their flights."
She stressed, however, the "big problem" yesterday was the weather.
"The low visibility has caused lots of delays."
All three companies claimed to have had their full complement of staff on duty at the airport yesterday and have rejected any claim that lower-than-normal staffing may have contributed to the backlogs.