PARIS (Reuters) - The head of Air France-KLM (AIRF.PA) said on Monday he was worried about lack of progress in talks with striking French pilots as the airline predicted it would be forced to cancel more than half its flights for a second day on Tuesday.

Chief Executive Alexandre de Juniac said the positions of French pilots had hardened during weekend talks and expressed concerns about the strike's financial impact as well as the defection of previously loyal passengers to competing airlines.

"It is as though we had talked for 20 hours for nothing," he told a news conference, adding that the airline would lose 10-15 million euros a day during the strike, which began on Monday.

He said such losses could eventually push the group into loss, but declined to say how quickly that could happen.

Pilots are striking over the conditions for staff transferring to the group's Transavia low-cost unit, which Air France-KLM plans to expand as part of a new strategic plan. De Juniac said Transavia would buy 22-23 jets under the plan but the company and pilots cannot yet agree over what model to use.

(Reporting by Tim Hepher. Editing by Alexandria Sage)