BERLIN (AP) — A union representing pilots at German carrier Lufthansa says they will stage a two-day strike starting Wednesday unless the company makes a “serious” offer in talks over pay increases.

It would be the second strike in a week after pilots staged a walkout Friday that led to hundreds of flights being canceled.

The Vereinigung Cockpit union has called for a 5.5% raise for its members this year and an inflation-busting 8.2% increase in 2023. Pilots are also seeking a new pay and holiday structure.

The airline says those measures would increase its staffing costs by about 40%, or around 900 million euros over two years. It has instead 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.

Strong unions have traditionally ensured good conditions for workers in Germany, using strikes to press their demands in labor disputes.