French trade unions have launched a second round of protests against a government plan to raise the retirement age.  Thursday's strikes slowed travel for thousands of rail and air passengers and disrupted schools across the country.

More than a million people protested two weeks ago against the retirement measure, and unions voiced hope early Thursday of an even bigger day of protests.  

Union leaders said more than 230 demonstrations were planned nationwide Thursday.  

Fewer than half the national trains were running normally, and major cancellations were expected at Paris' two main airports.

The bill to increase the minimum retirement age from 60 to 62 passed France's lower house of parliament earlier this month and the upper house is set to approve it in early October.  

President Nicolas Sarkozy says the retirement age hike is necessary so the money-losing pension system can break even by 2018.

The French retirement age is among the lowest in Europe.

Some information for this report was provided by AP, AFP and Reuters.