BERLIN (AP) — German carrier Lufthansa says it is canceling almost all passenger and cargo flights Friday from its two biggest hubs, Frankfurt and Munich, due to planned strike action by pilots.

A union representing Lufthansa pilots said early Thursday that they will stage a walk-out after demands for a pay increase were rejected by management.

Lufthansa said some 800 flights would be canceled, affecting many travelers returning at the end of the summer vacation. The airline’s budget carrier Eurowings would not be affected, it said.

The union Vereinigung Cockpit accused Lufthansa on Thursday of failing to improve on their previous offer, leaving pilots no choice but to go on strike to press their demands.

According to Lufthansa, the company had offered a one-off increase of 900 euros ($900), amounting to a 5% increase for senior pilots and an 18% increase for those starting the profession.

The union had called for a 5.5% raise this year and an automatic above-inflation increase in 2023. In addition, pilots are seeking a new pay and holiday structure that the airline said would increase its staffing costs by about 40%, or some 900 million euros over two years.