The airline lost a German court bid to prevent its pilots from resuming strikes this week in a dispute that has caused almost 4,500 flight cancellations in a month.
The refusal by the Munich Labour Court to grant the airline an injunction means the pilots are on track for their longest-ever walkout at the carrier. It kicked off at midnight local time.
Today, 816 flights are cancelled, while tomorrow 890 flights will be cancelled, affecting 180,000 passengers. Lufthansa has said over half a million travellers in total will have been affected by the last six days of strike action, which started last Wednesday.
Almost 50 flights to and from UK airports for today and tomorrow have been cancelled.
The long-running dispute over wages has continued, with union Vereinigung Cockpit (VC) seeking a 20 per cent raise for its members (spanning the period from 2012 when the last accord expired, through 2017). That works out at 3.7 per cent a year, while Lufthansa has offered 2.5 per cent for a six-year period.
Last week it reiterated its offer to raise that to 4.4 per cent as well as a bonus payment, should the pilots concede on retirement benefits and other perks. VC said it was continuing walkouts due to the lack of a "negotiable offer" from the airline to compensate the pilots. The union once more said it regretted the impact its strikes are having on passengers, cabin crew and ground staff.
It has organised 15 strikes since April 2014.
Lufthansa's share decline for the year is at 15 per cent.