In a statement released late on Wednesday, the airline said the strike had grounded a total of 1,800 flights scheduled for Wednesday and Thursday, affecting more than 215,000 passengers.
Pilots’ union Vereinigung Cockpit decided to extend its two-day strike to Friday, further increasing pressure on the airline.
The union, which represents 5,400 pilots at Lufthansa, is demanding a 3.7 percent annual pay rise for its members.