Ryanair has cancelled up to 28 flights from Irish airports to and from France, Spain, Portugal and the Netherlands due to a strike by French air traffic controllers while Aer Lingus has also warned passengers of lengthy delays.
The cancellations include flights to and from Dublin, Cork, Knock and Shannon to Faro, Nice, Barcelona, Carcassonne and Eindhoven.
Delays and possible further cancellations are expected and passengers are advised to check Ryanair's website for updates.
The airline said it had been forced to cancel up to 200 flights across its network today and that delays of up to six hours should be expected on flights to and from France and those flying through French airspace.
“In order to minimise disruptions on the rest of our network Ryanair has been forced regrettably to cancel a total of up to 200 flights which is approximately 12 per cent of Ryanair’s total schedule of over 1,600 flights today,” it said in a statement.
The airline said delays will continue this evening as the backlog of delayed flights rises.
The situation will be worse tomorrow and 250 flights are due to be cancelled, mainly to and from France and Spain.
Customers will be contacted by email and SMS later today and offered a choice of travelling on later flights or full refunds.
The airline apologised for the delays and cancellations.
It is asking customers who want to rebook their flights to avoid doing so for later today or tomorrow because of the likelihood of further disruption and cancllations.
A spokeswoman for Aer Lingus said the airline had not cancelled any flights today but warned that passengers could expect delays of up to three hours on flights to France, Spain, Portugal and the Canary Islands.
She said intending passengers should still come to the airport and check in. Updated flight information is available on the airline's website.
The airline plans to operate a full schedule tomorrow but flights to Spain, southern France, Belgium and the Netherlands will be delayed.
The strike is affecting flights to and from France and those flying through French airspace. Today is the start of a six-day strike by the air traffic controllers.
France's civil aviation authority has estimated that three-quarters of flights will operate during the strike, with one in five flights to Spain, Portugal, Morocco, Tunisia and Algeria on schedule.
It asked airlines to cut flights by 20 per cent in airports in southern France to ease the pressure.
The strikers, who are attached to the Unsa-ICNA union, are protesting against planned cuts that they say would harm air traffic control services in France.
Ryanair called on the European Commission to remove the right to strike from Europe's air traffic controllers, who it said were "attempting to blackmail ordinary consumers with strikes".
The company said many of Europe's police forces and army personnel were not allowed to strike. Nor were air traffic controllers in the United States, "meaning the skies over the US cannot be closed or severely disrupted by air traffic control strikes or work to rule".