Lufthansa has cancelled 895 flights scheduled for Wednesday from six German airports as government workers called short-term strikes in the run-up to wage discussions later this week.
The airline said that its hubs in Munich and Frankfurt would see the most disruption, adding that some 87,000 passengers would be affected overall.
Public-sector workers doing ground handling and security checks were expected to walk off the job ahead of wage talks with the government on Thursday.
The ver.di union is looking for a 6% pay rise for its two million members.
Lufthansa, which is not part of the negotiations, deployed practices it has used during strikes by its own employees to prevent long lines and chaos at airports.
It cancelled flights ahead of the start of the strike action and urged passengers to check their flight status on LH.com.
Passengers with mobility limitations were cautioned that staff to assist them getting through the airport would be in short supply and that they should consider rebooking at no cost.
Of the cancelled flights, 545 were to or from Munich, where the strike was to last all day.
All intercontinental flights to or from there were cancelled for Wednesday, the company said.
Most international flights would operate from Frankfurt, where the strike period was to be from 4.30am to 3pm local time.
However, flights within Germany or Europe from Frankfurt were largely cancelled.
Other airports affected are Dusseldorf, Cologne-Bonn, Dortmund and Hanover.
Strikes are taking place at a number of facilities such as kindergartens and swimming pools.
Garbage pick-up and street cleaning in Munich were also affected.