German airline Lufthansa has cancelled 1,350 flights as its pilots protest against an early retirement scheme.
The cancellation of about 48% of scheduled services will affect around 150,000 passengers during the strike.
The pilots union will strike until 23h59 on 2 December. Short-haul, continental and inter-continental flights will be affected.
Passengers can check the status of their flight on a website created specifically for strike-affected travel. Check your flight status here.
Flights cancelled due to the strike can be rebooked free of charge.