Insolvent Air Berlin cancelled 32 flights today as pilots continued to call in sick ahead of a deadline for potential investors to submit bids for parts of Germany's second-largest airline.
Lufthansa's low-priced subsidiary Eurowings, which is renting aircraft as well as pilot and crew from Air Berlin, has also been forced to cancel some flights.
Berlin's Tegel airport and Düsseldorf airport, Air Berlin's hubs, were hit hard by the strike action, which also affects 42 planes run by Air Berlin on behalf of Eurowings and Austrian Airlines.
The ailing carrier was forced to cancel more than 100 flights, including transatlantic connections, as a result of the sick notices, causing chaos at several German airports.
Representatives from pilots' union Vereinigung Cockpit were not immediately available for comment.
Air Berlin filed for bankruptcy protection last month after its biggest shareholder, Etihad Airways, withdrew funding following years of losses.
An industry source said Air Berlin could lose 4 million to 5 million euros a day because of the cancellations.
It seems like sickness is in the air since their cancelled flights aren't.
"We are now in final discussions with investors" he said, warning that cancellations were costing the already bankrupt firm "millions of euros".
Some 200 of its 1,500 pilots suddenly called in sick.
While a German government loan is helping keep Air Berlin alive, the carrier has also been forced to scrap some long-haul destinations from September 25.
According to a report in Germany's Bild newspaper, the pilots are responding to a decision by Air Berlin's management to cut off negotiations over transferring 1200 pilots to a potential new buyer for the carrier.