The agency which coordinates air traffic across Europe has said normal operations have resumed after flights were hit by delays due to a technical failure.
Eurocontrol says there was a failure of its Enhanced Tactical Flow Management System, which has also had an impact on its flight plan system.
The Dublin Airport Authority had advised passengers to check the latest flight information with their airlines.
Aer Lingus said it was forced to cancel six flights between Ireland and the UK as a result of the technical problem.
The airline says it is not expecting any further flight cancellations this evening or knock-on effects on tomorrow's schedule, and apologised to the passengers affected saying it was due to circumstances beyond their control.
Ryanair also cancelled a small number of flights due to the Eurocontrol fault, while some flights are also experiencing delays
Eurocontrol said flight plans which were filed before 11.26am Irish time this morning were lost and airlines were requested to refile plans for all aircraft that have not yet departed.
The ETFMS is involved in regulating the flow of flights around Europe.
Eurocontrol says that Air Traffic Control has not been directly affected by the problem and there are no safety implications arising from the incident.
Eurocontrol is an intergovernmental organisation with 41 member states, which coordinates air traffic management across Europe.
The issue with the ETFMS has been identified and work is progressing to recover the system, which is expected to occur late this evening. Aircraft operators are requested to refile any flight plans for flights not yet operated and that were originally filed before 10.26UTC— EUROCONTROL (@eurocontrol) April 3, 2018