Lufthansa said the cancellations would affect some 100,000 passengers.
German airline Lufthansa said Thursday it is canceling 830 flights on Friday after a pilots' union said it would extend strikes to a third day in a long-running dispute over wages.
Lufthansa said the cancellations would affect some 100,000 passengers booked on short- and medium-haul flights.
Long-haul flights will be operating, as will flights run by other Lufthansa group airlines such as Eurowings, Swiss and Austrian Airlines, the airline said.
Maintaining that the airline, Germany's largest, has been posting significant profits for years, the Cockpit union has demanded a 3.66 percent annual raise for the past five-and-a-half years.
Lufthansa has countered with a significantly lower offer, and has offered to bring in an arbitrator.
The latest strike by Cockpit is the 14th since April 2014 in the long-running dispute. It comes as Lufthansa restructures to meet increasing competition from Gulf airlines and European budget carriers.
"With a demand of 20 percent wage increases we cannot make Lufthansa fit for the future," said Lufthansa executive Harry Hohmeister.
With the Friday cancellations, Lufthansa said overall it has had to cancel 2,618 flights this week, affecting 315,000 passengers.