Deutsche Lufthansa AG’s Eurowings faces more walkouts this week as a contract dispute with cabin crew intensifies after a union rejected arbitration. The two sides failed to reach an agreement in talks over the weekend as the UFO union balked at the low-cost unit’s offer, which included a pay increase of 7 percent on average, Eurowings said in a statement. The carrier was mostly grounded by a strike on Thursday, causing more than 400 of 555 flights to be scrapped. The flight attendants have said they will halt work on two unspecified days this week unless a better offer is made. “Evidently, the UFO is pursuing goals that have nothing to do with the open aspects of the contract negotiations,” Joerg Beissel, Eurowings’ personnel chief, said in the statement. Unions have used contract disputes to disrupt plans by Lufthansa Chief Executive Officer Carsten Spohr to cut costs to better compete with the likes of Ryanair Holdings Plc and EasyJet Plc. Eurowings is at the center of the effort, and Spohr is pushing to expand the unit into Europe’s third-largest discount airline. Aside from the Eurowings cabin-crew feud, Lufthansa has yet to reach a deal with mainline pilots. The UFO union called a 24-hour walkout at Eurowings on Thursday to push for higher pay, and simultaneously called a stop at Lufthansa’s Germanwings unit, which flies under the Eurowings brand, over conditions for part-time workers. Eurowings called on the union to return to the negotiating table this week. UFO is flexing its muscle amid competition with German services union Ver.di about representing cabin crews. Ver.di asked members at Eurowings to walk out last month in a protest that resulted in only a handful of cancellations.