* Businessman Alexander Skora plans bid for Air Berlin
* Wants to return Air Berlin to holiday carrier roots
* Says Lufthansa, easyJet should get the other routes
* Other bids may come from Condor, former EnBW CEO Claassen (Adds further details of Skora's proposal, background)
FRANKFURT/BERLIN, Sept 4 (Reuters) - A German businessman joined the field of potential bidders for insolvent Air Berlin on Monday, proposing to focus on only a few routes to holiday destinations.
Air Berlin, Germany's second-largest airline, filed for bankruptcy protection in August after shareholder Etihad Airways withdrew funding following years of losses.
Now the carrier is to be carved up, most likely among several buyers, with about 140 leased aircraft and valuable take-off and landing slots in Germany up for grabs.
Skora, who owns a hostel in Berlin and says he earned a pilot's license in the United States, is looking at Air Berlin's books and will then decide whether to submit a formal bid for some of its assets, he told Reuters on Monday.
Any bid would be made jointly with a consortium of investors from Israel, Canada and the United States, he added, without providing details.
His proposal would see Air Berlin return to its roots as a holiday carrier and pass on long-haul and a number of European destinations to German flagship carrier Lufthansa and Britain's easyJet.
"I believe strongly that it is possible to continue flying with the basic business with which everything started. I mean routes such as Majorca and other selected destinations," he said in a statement earlier on Monday.
Lufthansa has government backing to take over large parts of Air Berlin. EasyJet and Thomas Cook's Condor are also seen as likely bidders.
German weekly Der Spiegel reported on Friday that Utz Claassen, a former chief executive of German utility EnBW , was also bidding for Air Berlin assets with a "highly potent and very reputable international investor".
In an interview with daily Handelsblatt, Claassen declined to confirm his interest, citing confidentiality.
Ryanair said last week it would not submit a bid, and German aviation investor Hans Rudolf Woehrl stepped back from the process on Thursday to search for a partner.
Former motor racing driver Niki Lauda told Reuters on Sunday he was working on a bid to buy back Air Berlin's Niki unit.
Bidders for the assets must submit offers by a Sept. 15 deadline, and a decision could come on Sept. 21, three days before the German national election.
Air Berlin is being kept in the air thanks to a 150 million euro ($178.50 million) government loan, which officials say will last the airline for up to three months. ($1 = 0.8403 euros) (Reporting by Maria Sheahan and Nadine Schimroszik; Editing by Mark Potter)