BERLIN — German airline Lufthansa has cancelled hundreds of flights at its budget unit Eurowings, affecting some 40,000 passengers, because of a strike by cabin crew.

The airline says about 400 flights have been cancelled Thursday, including most connections inside Germany.

Many of its European flights have also been cancelled but long-distance flights and those from Frankfurt and Munich aren’t affected.

The UFO union called the 24-hour strike starting at midnight after arbitration proceedings failed to achieve an agreement late Wednesday.

Members are seeking concessions on issues including pay, working conditions and pensions.

Eurowings also operates flights under the Germanwings brand. The airline said customers should check its website to see whether their flight is affected.