Ryanair has cancelled 420 flights on Friday, impacting 80,000 passengers, due to an air traffic control strike in France that will limit overflights.
France's DGAC aviation authority earlier this week asked airlines to halve their flight schedules on Friday due to the planned strike.
Ryanair, Europe's largest airline by passengers carried, said it will mainly be impacted by the limitation on overflying France, with a number of the affected flights departing from Dublin.
"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 to manage overflights of France during strikes, the statement said.
Meanwhile, Aer Lingus has cancelled four flights between Dublin and Paris on Friday due to the industrial action.
The airline says passengers due to travel can change their flight bookings free of charge via their online booking facility or call centre.
France's SNCTA air control union has cited inflation and its demand to hire more people as the reasons for the walkout.