Lufthansa pilots will hold another eight-hour strike at Munich airport on Wednesday, which will be the third strike by the airline's flight crew within two weeks.
Union Vereinigung Cockpit said the flight crew are seeking to increase the pressure on Lufthansa in negotiations over an early retirement scheme. They held a strike at Lufthansa’s LCC subsidiary Germanwings at the end of August, followed by another strike at Frankfurt last week.
The proposed strike at Munich will run from 0800-1600 GMT, the union said.
While Lufthansa's lucrative long-haul flights were spared from last week's Frankfurt walkout, the union said on Tuesday that this time the strike would affect all flights leaving Munich airport.
Lufthansa said it could not yet say which flights would be affected and described the industrial action as "incomprehensible".
Lufthansa shares fell after the announcement and were down 1.5% at €13.60 by 0814 GMT.
Vereinigung Cockpit represents up to 5,400 of Lufthansa's 9,000 pilots, and the previous two strikes have cost the airline more than €10 million (US$12.9 million) in operating profit.
A three-day walkout by flight crew in April wiped €60 million from the airline's first-half operating profit.