Cabin crew union UFO has called for a walkout at Lufthansa’s German operations on Thursday and Friday. FRANKFURT: Lufthansa, Germany’s biggest airline, has filed a motion with a Frankfurt court to prevent a flight attendants’ strike scheduled for this week, a company spokeswoman said on Tuesday. Cabin crew union UFO has called for a walkout at Lufthansa’s German operations on Thursday and Friday. In addition to a dispute over pay and pensions, UFO has also fought with the airline in court for months over the union’s legal status.