German labor union Verdi has called for warning strikes at the nation’s major airports on Friday by public service, air security, and ground-traffic workers.

The Feb. 17 action would affect airports in Frankfurt, Munich, Stuttgart, Hamburg, Dortmund, Hannover, and Bremen, Verdi said in a statement Wednesday. The actions typically affect domestic flights.

The union is calling for wage increases for workers amid significant increases in costs of living from higher energy prices and record inflation.