The Berlin-based airline booked losses amounting to 1.2 billion euros ($1.3 billion) for the last two years, and depends on cash infusions from key shareholder Etihad for survival.

"We need to find a partner in 2017, and Lufthansa is a possible one," said Air Berlin chief executive Thomas Winkelmann.

"I will look at everything that makes sense for Air Berlin and secures jobs in the long term," he told Die Zeit weekly in an interview.

Executives from Germany's second-largest airline presented a massive restructuring plan in late September that included renting 38 aircraft with crew to Lufthansa and slashing 1,200 jobs -- or one in seven of its workforce.

Amid its restructuring, it has also been hit by a string of flight cancellations and severe delays, including over the recent Whitsun long weekend.

Winkelmann apologised to his clients for the problems, saying: "I am sorry for the delays. I myself am furious when there is a delay of more than ten minutes."

But beyond the bad publicity caused by the delays, the airline would also have to pay a price.

According to Germany's biggest daily Bild, compensation payments over the Whitsun weekend alone are expected to reach more than half a million euros.