Insolvent German airline Air Berlin is scrapping more long-haul flights, this time to the Caribbean from Duesseldorf, to reduce its long-haul fleet and cut costs while it seeks investors. 

The routes to destinations in places such as Mexico, Cuba, the Dominican Republic and the Antilles will end from September 25, the carrier said. 

Air Berlin, Germany's second-largest airline, was forced to file for bankruptcy protection last month after shareholder Etihad Airways withdrew funding following years of losses. 

Its planes are being kept in the air thanks to a €150m government bridging loan, which will last until the middle of November at the latest. 

Investors are currently lining up for the airline, with Lufthansa seen as in pole position to take on large parts of Air Berlin. 

Bidders have until September 15 to submit binding offers for the assets, with a decision possible as early as Sept. 21, three days before a German national election. 

Aviation investor Hans Rudolf Woehrl last night said he had submitted a bid for the whole of Air Berlin. Air Berlin confirmed today it had received a letter from Woehrl and was reviewing it. 

Air Berlin also said today it was bringing forward again the cancellation of services from Berlin to Los Angeles and San Francisco, and from Duesseldorf to Boston, to September 25. 

It had previously planned to cancel them on October 1. 

Last week, it also said it was dropping flights from Berlin to New York and Miami, and from Duesseldorf to Orlando as of September 25.