European airlines say hundreds of flights were delayed or cancelled on Thursday due to a strike by air traffic controllers in France.
Airlines Easyjet, Ryanair, British Airways and Aer Lingus each reported numerous flights cancelled due to the strike, which was set to impact thousands of passengers.
More than 300 flights were estimated to be cancelled, as airlines in Europe reduced their offering by 15%, according to lobby group Airlines for Europe (A4E).
The strike, which is expected to last for 35 hours, is the latest of several walk-outs this year by French air traffic controllers in protest at France's controversial labour reforms passed in July in an effort to jumpstart the country's flagging economy.
The labour action drew criticism from A4E lobbyists representing several airlines affected by the strike.
"The demands of increasingly mobile European citizens and businesses cannot be taken hostage by localised industrial action. It is about time to minimise the impact of these strike actions," A4E chief Thomas Reynaert said, also criticising a lack in measures from European authorities to prevent such strikes.
Europe has already seen several strikes this year by air traffic controllers in Italy, Belgium, Greece and France, leading to thousands of cancelled and delayed flights.
A demonstrator kicks tear gas during clashes with French riot police during a demonstration against controversial labour reforms of the French government in Paris on Thursday.