Around 1,000 Lufthansa flights will be affected by a pilot strike that began at midnight targeted at short and medium-haul routes.
The German airline said that of the 3,000 flights due to take place across the group, 1,000 would be cancelled because of the strike action.
But despite the pilot walk-out, Lufthansa would still fly around 500 short and medium-haul services.
The strike follows on from industrial action taking place yesterday which targeted long-haul services.
Lufthansa’s long-haul network will also see some cancellations, with 52 of the 176 long-haul services affected.
This is partly a consequence of yesterday's strike as the aircraft concerned are not yet back where they need to be to operate today's services as scheduled.
“The services of Germanwings, SWISS, Austrian Airlines and Brussels Airlines are not affected, and will operate as scheduled,” the airline said. Lufthansa Cargo flights are also unaffected.
The strikes come as negotiations continue between the airline and union over cost reduction measures.
The union said the airline had rejected a proposal to reduce costs by €500m under the condition that aircraft and pilots would not be transferred to low-cost subsidiaries in Germany and abroad at an early September meeting.
