A six-day strike by French air traffic controllers has caused major travel disruption for many travellers.
Ryanair was forced to cancel more than 160 flights from its schedule today.
These included flights from Dublin, Cork, Knock and Shannon to destinations including Madrid, Barcelona, Nice and Faro.
Departures from and arrivals to Paris Beauvais, Marseilles and London Stansted were also affected.
Ryanair customers are advised to check the status of their flight on the airline's website.
The carrier has said affected customers will be updated on their flight status via email or phone.
Ryanair is also advising customers who want to rebook flights to avoid rebooking them today and tomorrow as there is a possibility of further disruption within that time.
Aer Lingus has not cancelled any flights today but around 20 were delayed.
The airline said passengers travelling to or from France, Spain, Portugal and the Canary Islands may experience delays of up to three hours.
Aer Lingus is advising customers to check their flight status online and to arrive early if checking in at the airport.
Meanwhile, CityJet has said none of its flights from or into Ireland have been affected.
The strike, by a leading French union, centres on planned changes to European air traffic according to traffic flows rather than national borders, which the union argues will undermine an efficient air navigation service in France.