FRANKFURT (Reuters) - Airline entrepreneur Hans Rudolf Woehrl is interested in insolvent Air Berlin (>> Air Berlin Plc), a spokeswoman for his company INTRO-Verwaltungs GmbH told Reuters, responding to a media report saying he was planning a bid.

She said it was the only way to avoid creating a German monopoly. Lufthansa (>> Deutsche Lufthansa) is the sole major player remaining.

German magazine Capital earlier reported that Woehrl was thinking of teaming up with other investors to make a takeover offer for Air Berlin, citing people familiar with the matter.

"INTRO already declared its interest years ago to take a majority stake in the Air Berlin group jointly with additional investors. This interest still exists," the spokeswoman said in an emailed statement, adding other investors were involved.

"We think Air Berlin is meaningful only as a whole, because that is the only way to prevent a monopoly at the expense of passengers in Germany."

Woehrl made a name for himself in Germany's aviation world when he bought German airline Deutsche BA from British Airways -- now part of IAG (>> International Consolidated Airlines Group) - for 1 euro ($1.17) in 2003.

Air Berlin, Germany's second-largest airline, filed for bankruptcy protection on Tuesday after shareholder Etihad Airways withdrew funding following years of losses.

The German government has granted a bridging loan of 150 million euros to allow Air Berlin to keep its planes in the air for three months and secure the jobs of its 7,200 workers in Germany while negotiations continue.

"No offer has been submitted so far because there are concerns that the loan by the government is meant to deliberately promote a monopoly structure that seeks to block offers from investors right from the start," the INTRO spokeswoman said.

Air Berlin has been in preliminary talks with a total of three aviation firms, including Lufthansa (>> Deutsche Lufthansa), over the sale of its assets, Chief Executive Thomas Winkelmann told a newspaper.

A source has said easyJet (>> EasyJet) was also part of the negotiations, while Thomas Cook's (>> Thomas Cook Group) German airline Condor said it was ready to play "an active role" in Air Berlin's restructuring, without being more specific.

(Reporting by Christoph Steitz; Editing by Jeremy Gaunt)