Lufthansa canceled 50 flights Thursday ahead of a planned 24-hour walkout by cabin crew at six airports on Friday.
Lufthansa expects that the strike will cause the airline to cancel two-thirds of its 1,800 flights on Friday.
Thursday's cancellations affected domestic and European services as well as several international flights, including New York-Frankfurt and Hong Kong-Munich, according to the carrier's website.
The 24-hour work stoppage on Friday will affect flights at airports in Berlin, Dusseldorf, Frankfurt, Hamburg, Munich and Stuttgart.
Walkouts last week and earlier this week grounded hundreds of Lufthansa flights.
The Independent Flight Attendants Organization is seeking a 5% pay increase backdated to April after three years of wage freezes. The union also opposes the use of temporary cabin crews on Lufthansa flights, according to a union spokesperson.
Follow Gay Nagle Myers on Twitter @gnmtravelweekly.