The company said in a statement that close to 800 flights had been cancelled, disrupting the travel plans of about 100,000 passengers.

This “affects our passengers extremely harshly and disproportionately,” it said, adding it expects a return to its normal schedule on Friday.

German airport association ADV estimated that more than 460 flights will be cancelled, with almost 70,000 passengers affected.

Departure boards for Frankfurt and Munich, Lufthansa’s hubs in Germany, showed most flights were cancelled for the day, including to overseas destinations.

Lufthansa earlier said it would try to rebook passengers on its other airlines or partner airlines before returning to its normal schedule on Friday.

The walkout, organised by pilots’ union VC and flight attendants’ union UFO, comes as the Berlinale film festival starts in the German capital on Thursday, and politicians and military officials gather for the Munich Security Conference, which will commence on Friday.

Pilots are in conflict with Lufthansa’s namesake core airline and its cargo division over pensions.

Their union declared readiness to strike after a ballot last year to pressure the company into granting more generous retirement benefits.

Talks have since resumed but have been intermittent and without result.

Lufthansa, which has described its core airline as a “problem child”, says there is no financial leeway for the demands.

Separately, the UFO union of flight attendants called on its members at Lufthansa’s CityLine subsidiary to strike over the planned shutdown of its flight operations and “the employer’s continued refusal to negotiate a collective social plan”.

“The simultaneous industrial action by pilots is a coincidence, but one that is welcome,” said UFO union representative Harry Jaeger.

“We want to annoy management, not passengers,” he added.