Ground staff at German flagship carrier Deutsche Lufthansa will stage a strike on Wednesday amid a wage dispute, further adding to travel disruptions during the busy summer travel season.

Strikes and staff shortages have already forced airlines to cancel thousands of flights and caused hours-long queues at major airports, frustrating holidaymakers keen to travel after COVID lockdowns.

The walkout by staff at Lufthansa’s ground units this Wednesday will lead to additional cancellations and delays, Verdi said, as it includes workers with key jobs such as aircraft maintenance and pushing back aircraft from the gate so they can head to the runway for takeoff.

The strike will affect German airports including Frankfurt, Duesseldorf and Berlin.

Verdi had last month demanded a 9.5% pay rise, or at least 350 euros ($368) more per month, for around 20,000 workers who it says are being squeezed by inflation and overworked due to staffing shortages at airports.

Management presented an offer on July 13, which Verdi says is insufficient to offset soaring inflation, which hit 8.2% in June.

The workers “urgently need more money and they need relief – for themselves and for the passengers”, Verdi deputy chief Christine Behle said in Monday’s statement.