The strike by Lufthansa pilots in support of a pay demand is in its second day on Thursday, with the German flagship carrier cancelling 912 flights for the day.
The strike has hit the travel plans of some 100,000 long-and-short-haul passengers.
The Vereinigung Cockpit (VC) Pilots’ Union announced that the strike, the 14th in a dispute stretching back to April 2014 would be extended to a third day on Friday, from the two originally planned.
The stoppage, aimed at pressing demands for a backdated pay increase of 22 percent over the five years to April 2017, grounded 876 flights on Wednesday.
In total, 215,000 passengers have been affected over the first two days.
Report says the Friday action is likely to hit primarily short-haul flights taking off within Germany.
The company said it planned to service all its long-haul destinations on Friday.
Airports across Germany were noticeably quieter than usual, with Munich badly hit as well as the main hub near Frankfurt.
Group human relations head Bettina Volkens repeated a call for the union to enter into arbitration with Europe’s largest airline.
However, VC spokesman Joerg Handwerg rejected arbitration, saying pilots had been “uncoupled from changes in pay in Germany for the past five years” and that they were no longer prepared to be left on the sidelines.
Chaos was avoided by many Lufthansa passengers simply staying away from airports.
The company was providing ongoing information on its website and arranging alternatives for stranded passengers.