Air passengers leaving and arriving into Ireland can expect more cancellations and delays today.
A fault at Air Traffic Control in the UK has now been fixed, however the knock-on effect to flights right across Europe and beyond is likely to continue for a number of days.
It's not clear what caused the system to break down but it meant that take-offs and landings had to be processed manually.
Hundreds of passengers were left stranded at Irish airports.
Anyone due to fly today is being told to contact their airline before setting out to the airport.
The UK Air traffic control operator, NATS posted this apology online, from operations director Juliet Kennedy.
"Our absolute priority is safety and we will investigate thoroughly what happened. Again, I would like to apologise."
