Ryanair said it has cancelled 420 flights today due to a strike by French air traffic controllers.
The cancelled flights affect 80,000 passengers and include a number of flights from Dublin Airport.
Ryanair said it has notified affected customers via email or SMS informing them of the cancellations.
France's DGAC aviation authority earlier this week asked airlines to halve their flight schedules today due to the planned strike.
Ryanair said it will mainly be impacted by the limitation on overflying France. It flies up to 3,000 flights a day across Europe during its peak season.
"It is time that the EU step in and protect overflights so that European passengers are not repeatedly held to ransom by a tiny French ATC union," Ryanair Operations Director Neal McMahon said in a statement.
Other air traffic control centres should be allowed manage overflights of France during strikes, the statement said.
Meanwhile, Aer Lingus cancelled four flights between Dublin and Paris today due to the industrial action.
The flights are EI524, EI525, EI528 and EI529.
The airline said passengers due to travel can change their flight bookings free of charge via the airlines online booking facility or call centre.
Some Aer Lingus passengers will also be affected by flight cancellations on the Dublin Heathrow route on Monday, as Heathrow airport plans to reduce noise during Queen Elizabeth's funeral.
Six flights between Dublin and Heathrow are affected - EI160, EI165, EI168, EI169, EI176 and EI177.
Two flights between Belfast and Heathrow are also affected - EI1932 and EI1935.
Aer Lingus said it has re-accommodated as many passengers as possible on other flights and will be contacting passengers individually.
Flight changes free of charge are also being offered.
Additional reporting Reuters