Passengers at Belfast International experienced delays

All flights to and from Northern Ireland's three airports were affected by the technical hitch on Thursday.

All UK flights were suspended for a time because of the shutdown.

However, all UK flights were fully operational again after 0900 BST.

The West Drayton centre processes details of flights in and out of the UK.

Flights in and out of Belfast City Airport, Belfast International Airport and the City of Derry airport were all affected and many flights were cancelled.

However, by Thursday evening, most flight schedules had returned to normal.

We haven't had any flights depart the airport this morning, so we are talking probably of the order of two hours delay Uel Hoey Belfast International Airport

Earlier on Thursday, City of Derry airport said passengers were experiencing delays.

However, a spokesman said passengers should check in as normal.

Uel Hoey of Belfast International Airport said there had been delays in and out of the airport.

"We don't have any cancellations and the airport operations staff are working to minimise disruption to passengers," he said.

"We would expect that there would be delays to flights throughout the morning while the overall system rectifies itself.

"The general advice we would give to passengers is to check in for their flights as normal."