Germany's flagship airline Lufthansa said 830 domestic and European flights were being scrapped on Friday, affecting more than 100,000 passengers, on the third day of a strike by pilots demanding higher pay.

More than 2,600 flights have been cancelled since the start of the walkout, which the pilots union Vereinigung Cockpit (VC) on Thursday announced would be extended into Saturday.

The strike is Lufthansa's 14th since April 2014.

VC are demanding a pay rise of an average of 3.66 percent per year, retroactive for the past five years. The management are offering 2.5 percent.

Austrian Airlines and Swiss -- part of the Lufthansa group -- have tried to pick up some of the slack by expanding their service to Germany.  

The group's other airlines -- Germanwings, Air Dolomiti and Brussels Airlines -- have not been affected by the strike.

The top-selling daily Bild says the strike is costing Lufthansa some 10 million euros ($10.5 million) a day.