They announced the cancellation of more than 100 flights on Tuesday.
"We worked hard to be able to make this offer, with help not only from experts but also supportive comments and suggestions from employees, passengers and business partners of Air Berlin", the Bavarian airline tycoon wrote in a Facebook post late Sunday. "Air Berlin has informed us on short notice that numerous flights operated by Air Berlin. can not be staffed", says Eurowings.
The airline's chief executive, Thomas Winkelmann, accused pilots of "playing with fire", as the cancelled flights would cost the company several million euro, making it less attractive to potential buyers. "That is the only way to secure as many jobs as possible", Mr Winkelmann said.
Germany's giant services sector union Verdi expressed solidarity with the absent pilots and warned that more workers could call in sick. Verdi is likewise urging staff members to go to work "in order not to jeopardise jobs", but notes: "It can not be ruled out that this will occur with other employees too".
Air Berlin yesterday disclosed plans to terminate all its flights to Caribbean destinations on 25 September.
The cancellations come on top of a previous announcement that the airline will abandon flying between Berlin and Abu Dhabi, Chicago, Los Angeles and San Francisco, plus the Düsseldorf-Boston route. Germany's government has backed a €150 million ($179 million) bridging loan, and talks with potential investors are under way.
German press estimated that over 100 national and worldwide flights were to be grounded, affecting schedules at Berlin's Tegel airport, Düsseldorf, Munich and others.