* Two-day strike to run until Friday, 2259 GMT
* Germanwings operates 60 pct of planned flights
* Union says still waiting for decent offer (Recasts with Germanwings comment, adds pilot comment)
FRANKFURT, Feb 12 (Reuters) - Lufthansa's budget airline Germanwings called on striking pilots to return to the negotiating table on Thursday, as they began a two-day strike which will cost the carrier more than 10 million euros.
The Vereinigung Cockpit (VC) pilots union strike, designed to put pressure on Lufthansa's management in a long-running row over early retirement benefits, is due to run until 2259 GMT on Friday and will affect hundreds of departures across Germany.
Germanwings said it was operating more than 60 percent of the 900 flights normally scheduled for the strike period thanks to managers who are pilots stepping in, and crews and planes hired from other companies.
Lufthansa wants to change a scheme that lets pilots retire at 55 and still receive a portion of their pay until the regular state pension payments kick in. The airline wants to increase the earliest age at which its new pilots can retire to reflect increasing life expectancies, and to cut costs.
The VC pilots staged 10 strikes last year, affecting hundreds of thousands of passengers and wiping up to 200 million euros ($226 million) off Lufthansa's operating profit at a time the airline is trying to reduce costs to keep up with rivals.
"This latest strike doesn't make sense," Germanwings Managing Director Thomas Winkelmann said.
"No one understands why a young co-pilot should demand the right to take early retirement in 30 years at conditions that are out of proportion with elsewhere and financed by the employer," he said.
The pilot's union said it was trying to force management to make a better offer and hoped this strike would have an effect.
"We await, after a year of almost pointless discussions, an offer that we can use as a basis for negotiations," VC board member Markus Wahl told Reuters TV.
The pilots have also requested that management enter mediation talks on plans for the expansion of budget flights, which Lufthansa has refused. Pilots oppose the way Lufthansa is pushing through the expansion by using a small business that is not subject to the same collective labour agreements as pilots working for its Lufthansa and Germanwings businesses.
Like rival Air France-KLM, Lufthansa wants to increase low-cost operations to win back market share lost to the likes of Ryanair and easyJet, which are expanding in its home market.
$1 = 0.8818 euros Reporting by Maria Sheahan, Reuters TV, Victoria Bryan and Peter Maushagen; editing by Clarence Fernandez and David Clarke