A union representing Lufthansa pilots has called a one-day strike at the German airline's short-haul and middle-distance operations on Wednesday — the latest in a string of walkouts.

The Vereinigung Cockpit union has hit various Lufthansa units with around a dozen short-term walkouts over recent months. The dispute centers on the airline's plans to cut transition payments for pilots wanting to retire early, which the union wants to see maintained.

The union announced the latest strike on Monday night, saying that talks last week failed to make any progress. It said Lufthansa's lower-cost Germanwings and Eurowings units won't be affected.

Traditional national carriers such as Germany's biggest airline are being squeezed both by European budget carriers and major Gulf airlines. Lufthansa has announced plans to launch budget long-haul services.