More than 900 flights are to be cancelled by German airline Lufthansa on Monday due to a strike, affecting 113,000 passengers.
Members of cabin crew union UFO are taking part in a week-long walk-out in a row over retirement benefits.
The union announced the walk-out at Frankfurt, Munich and Düsseldorf airports from 3.30am on Monday.
Lufthansa said 929 flights would be cancelled as a result of the industrial action.
Short and long-haul flights under the Lufthansa brand at the three airports will be affected.
Lufthansa has warned of disruptions to its services today and tomorrow as a result of industrial action by some of its pilots.
Reuters reports that the German airline has cancelled 1,450 flights.
The strike, organised by the pilots union Vereinigung Cockpit, will begin at 1pm CEST (12 noon UK time) today and last until 11:59pm CEST (10:59pm UK time) on Tuesday.
Lufthansa said it would initially affect short- and medium-haul flights and would be extended to intercontinental services on Tuesday.
The airline advises all passengers to check the status of their flight
Strike action has led to the cancellation of dozens of flights to and from the UK and Ireland by German airline Lufthansa.
Around 100 flights have been cancelled at airports in London, Manchester, Birmingham, Newcastle, Glasgow, Aberdeen, Edinburgh and Dublin.
The one-day strike, which is due to a pay dispute, will affect Frankfurt, Munich, Dusseldorf and Hamburg.
As a result, only about 20 of more than 1,650 scheduled short-haul flights will operate, long-haul services will also be hit.
Passengers affected by cancellations can re-book for free, Lufthansa said.
German airline Lufthansa has cancelled dozens of flights to and from the UK and Ireland due to strike action.
Around 100 flights - including departures and arrivals - have been cancelled at airports in London, Manchester, Birmingham, Newcastle, Glasgow, Aberdeen, Edinburgh and Dublin.
The German airports affected by the strike are Frankfurt, Munich, Dusseldorf and Hamburg. the one-day strike, which is due to pay dispute, will result in only about 20 of more than 1,650 scheduled short-haul flights operating. The airline said many long-haul flights will also be affected.
Passengers affected by the cancellations can re-book for free, Lufthansa said.