Strikes to protest the French government's plans to raise the retirement age past 60 delayed flights, closed schools and frustrated commuters Thursday.

President Nicolas Sarkozy has said such a low retirement age is untenable as life spans increase.

Steel workers from the nearby Fos-sur-Mer ArcelorMittal plant take part in a demonstration in Marseille, France, Thursday. (Claude Paris/Associated Press)

But unions see his attempts to cut costs in France's over-stretched pension system as a blow to Europe's cherished social model.

France has one of the lowest retirement ages in Europe and Sarkozy wants to raise it to 61 or 62.

Some unions say the better solution is to raise workers' monthly contributions.

Workers for the government and private companies from Nestle to oil giant Total walked off the job across the country.

Striking train drivers reduced commuter traffic around Paris, although international train routes did not appear to be affected. Aviation authorities expected flights at Paris' Charles de Gaulle airport to be reduced by 10 per cent and those at Orly airport by 30 per cent because of the strikes.

About 14 per cent of teachers nationwide were on strike, and about eight per cent of hospital workers were off the job.

Germany recently raised its retirement age from 65 to 67.

France's retirement plans pale before the harsh austerity measures instituted by other European nations, including Greece, Ireland and Portugal, as those countries deal with their deficits.

Spain and Italy have also announced recent austerity plans as a debt crisis that started in Greece has weakened the euro and raised questions about the future of the currency shared by 16 nations.

With files from The Associated Press