Flights were temporarily suspended at Dublin Airport due to a "confirmed sighting of a drone over the airfield".
A spokesman said the flights were initially suspended due to safety reasons, but resumed at around 12.10pm on Thursday.
He said: "Flight operations have now resumed at Dublin Airport following an earlier drone sighting.
"We apologise for any inconvenience. The safety and security of passengers is always our key priority."
A picture posted by FlightRadar showed a number of flights being held and circling near Dublin Airport.
An earlier statement from Dublin Airport said: "For safety reasons we are temporarily suspending flight operations due the confirmed sighting of a drone over the airfield.
"Passengers should contact their airline's website for flight updates."
The incident comes just two months after dozens of drone sightings in Gatwick Airport saw 1,000 flights cancelled and an estimated 140,000 passengers affected ahead of Christmas.
The sightings over Britain's second-busiest airport caused the biggest disruption to the airport's operations since 2010, when a volcanic ash cloud grounded flights.
