Flights operated by Air Berlin will end by 28 October at the latest, the airline has said, as it works towards agreeing deals to ship off its assets.
The German carrier filed for insolvency in August, with a government loan keeping its planes in the air, so it has time to negotiate with investors for parts of the business.
Talks with Lufthansa and EasyJet are expected to run until Thursday, and then, once a deal for parts of its business is set, Air Berlin will wind down the rest of the operation.
Last month, EasyJet announced a proposal to take over parts of Air Berlin's short-haul business, saying they were consistent with the airline's "focused, city-based strategy in Germany".
The airline filed for insolvency after main shareholder Etihad refused to provide further financial support. Etihad said at the time that Air Berlin's business "has deteriorated at an unprecedented pace, preventing it from overcoming its significant challenges and from implementing alternative strategic solutions".
In the UK, Monarch Airlines announced it had ceased trading last week, with terror attacks in Tunisia and Egypt, increased competition, and the weak pound all flagged as reasons for its demise.
Administrators said 1,858 employees were made redundant, though a number of other firms, including EasyJet, have reached out to Monarch employees for opportunities.
Yesterday, the British Airline Pilots Association (Balpa) called for an investigation into the collapse of Monarch.
The union, which represents 400 ex-Monarch pilots who lost their jobs a week ago, is calling on the government to look into the circumstances surrounding the collapse of Monarch and the role of the firm's former financial backers.
Chair of the Transport Select Committee, Lilian Greenwood, said the committee will seek further information from the transport secretary when he appears before it next week.
She said: "We don't yet know the whole story behind this, but I expect that members will want to understand more of the detail. If there is any question of impropriety, the Committee will consider the appropriate channels for further investigation."