Staff at Lufthansa have walked out on strike in Frankfurt and Munich, forcing the cancellation of hundreds of flights.
Several airports were hit as the ver.di union called on ground staff to walk out ahead of negotiations on pay.
Reports suggest the action will continue until late morning.
Ahead of the strikes, Lufthansa, Germany's biggest airline, cancelled nearly 700 flights, affecting much of the morning's domestic and European flight schedule.
The union and Lufthansa are to meet tomorrow to discuss ver.di's demand for a 5.2 per cent pay increase over the next year for 33,000 Lufthansa employees.
Ver.di says Lufthansa's call for a two-year pay freeze until January 2015 and the extension of the work week by an hour is unacceptable.
