Talks began on Friday on carving up Air Berlin, which said on Tuesday it was filing for insolvency. German flag carrier Lufthansa (>> Deutsche Lufthansa) was first in the queue for meetings, ahead of other potential bidders.

"We have spoken with more than 10 interested parties, among them several airlines," Thomas Winkelmann was quoted as saying in an advance excerpt of an interview to be published on Sunday in Bild am Sonntag.

Winkelmann said he wanted a sale to be done in September at the latest.

"There won't just be one, but two or three bidders," he said, adding the long-haul, business and leisure routes were too separate as business areas.

German Deputy Economy Minister Matthias Machnig said it would not be possible to secure the takeover of Air Berlin (>> Air Berlin Plc) as a whole. "The model of Air Berlin as an independent airline has failed," he told German radio station rbb InfoRadio.

Germany's Hans Rudolf Woehrl, who bought German airline Deutsche BA from British Airways for 1 euro, threw his hat in the ring for Air Berlin on Friday and said he wanted to keep it flying after buying it.

Earlier in the week, a source familiar with the matter said easyJet (>> EasyJet) was among those in talks, and Thomas Cook's (>> Thomas Cook Group) German airline Condor said it was ready to play "an active role" in Air Berlin's restructuring.

Machnig said it would take several investors to offer Air Berlin and its employees a long-term future, reiterating that Lufthansa would not be the only buyer of the carrier's assets.

The head of Germany's advisory Monopoly Commission, Achim Wambach, told Die Welt that allowing Lufthansa to take over Air Berlin's route network would render large numbers of German domestic routes uncompetitive.

German federal Transport Minister Alexander Dobrindt has called for creating a German "national champion", a phrase Die Welt said had also set alarm bells ringing in Brussels.

He dismissed a complaint by Ryanair (>> Ryanair Holdings plc) over the handling of the insolvency, which Ryanair Chief Executive Michael O'Leary called a "conspiracy", saying O'Leary was welcome to play a role in Air Berlin's restructuring.

"I am entirely willing to discuss the matter," Machnig said.

(Reporting by Gernot Heller, Thomas Escritt and Victoria Bryan; Writing by Maria Sheahan; Editing by Toby Chopra)