The Lufthansa pilots, who filed their suit on Monday, believe they should be able to work until they're 65, assuming there's a younger co-pilot in the cockpit. Lufthansa allows this set-up on Cityline, its daughter airline which flies within Europe.

The company, however, has defended this practice. There's a big difference between two-hour and 15-hour flights, Lufthansa spokeswoman Amelie Lorenz said.

But age alone doesn't determine a pilot's fitness on long flights, according to the plaintiffs' attorney, Ekkehard Helmig. The captains had tried to resolve the issue for the past two years, Helming told the Tageschau television program.

New law prohibits descrimination

Anti-discrimination legislation became law in Germany this summer. It prohibits employers discriminating against the handicapped or based on religious beliefs or homosexuality. It also specifically prohibits age discrimination to try and prevent the widespread practice among German businesses of forcing out aging employees.

During the first day of the lawsuit against Lufthansa, the two sides were asked to see if they could come to some type of an agreement. They couldn't.

This means the court will re-convene in March with a ruling. The case is seen as a test for the new anti-discrimination legislation. Its outcome will guide other German labor groups who want to challenge perceived age discrimination.