UPDATE 2-Air Berlin in code-sharing talks with Air France
* Air Berlin CEO says could imagine Air France code-share
* Any such deal would cross airline alliance boundaries
* Parties aim for deal by summer - source
* Air Berlin CEO says alliances have 'crossed their peak'
BERLIN, March 4 (Reuters) - German airline Air Berlin is in talks with French carrier Air France-KLM on a code-sharing agreement as it seeks to offer its customers more routes via partnerships, its chief executive said.
"There are talks. Now we have to see what the outcome is," Wolfgang Prock-Schauer told journalists on Tuesday. "I could certainly imagine that we agree a partnership," he added.
A person close to the matter told Reuters that Air Berlin and Air France aimed for a deal by the European summer.
Such a deal would be unusual in the airline sector as Air Berlin, Germany's second-biggest airline after Lufthansa , is part of the Oneworld alliance of airlines, while Air France is part of rival group SkyTeam.
Air Berlin has been looking to expand via partnerships such as code-shares, which allow carriers to sell tickets for each others' flights, to cope with deteriorating finances following a period of aggressive growth in the last decade.
It announced in October 2012 that it had struck a code-share agreement with Air France and Etihad but in the end that deal went ahead without the German carrier.
Air Berlin currently has code-shares with Oneworld members such as British Airways and Finnair but also with non-members such as Air Seychelles and Air Serbia.
CEO Prock-Schauer downplayed the importance of airline groups such as Oneworld and SkyTeam, saying alliances had "crossed their peak" and were no longer of great importance to airlines.
"There is a lot of cross-alliance cooperation going on," he said.
He echoed Etihad, owner of close to 30 percent in Air Berlin's stock, which is not a member of an alliance and has said it would not join one.