The German pilot union Cockpit called Thursday for more than 700 pilots employed by Deutsche Lufthansa AG's subsidiary Cityline to observe a 36-hour strike in support of increased pay, dpa reported.
Cockpit said the strike, which began at midnight and was scheduled to end at noon Friday, was aimed at breaking a months-long deadlock in talks with the airline.
The union said the airports at Frankfurt, Munich, Hamburg, Dusseldorf, Berlin and Leipzig would be hit.
Lufthansa said it would transfer passengers to trains and other flights.
Cityline operates about 400 flights daily to domestic and European destinations.
The union called strikes lasting 24 and 36 hours, respectively, at Cityline and another Lufthansa subsidiary, Eurowings, in July.
Lufthansa has offered about 6 per cent more pay over a contract lasting up to two years. Cockpit has rejected the offer as not worth negotiating but has not specified its demands.
Flights at Lufthansa, Germany's largest airline, are returning to normal after a five-day strike by ground and cabin staff that began at the end of July.