By Jens Hack MANCHING, Germany (Reuters) - More than 20,000 workers from European aerospace group EADS took to the streets in Germany on Thursday to protest against restructuring plans they fear could cost thousands of jobs. Protests were held at about 30 sites, from the company's Airbus factories near Hamburg in the north to its Eurofighter jet assembly plant in Bavaria's Manching in the south. "This has been a clear warning that the employees of EADS will not accept decisions made to their disadvantage and over their heads," said Ruediger Luetjen, head of the company's European works council and an IG Metall union representative. EADS, part-owned by the French and German governments, is planning to combine its defense and space subsidiaries next year and has said it might sell some operations. The company is due to announce details of the shake-up on December 9, but labor representatives have called on EADS to show its hand sooner to ease workers' concerns after reports that several thousand jobs will be axed. EADS has about 140,000 employees around the world, of which about 50,000 are in Germany. "What is happening here is just not right," said Peter Stoerecker, one of about 1,000 workers who joined a rally in Manching. Workers waved red flags emblazoned with the logo of Germany's IG Metall union and blew on red plastic whistles as they marched through snowy weather, accompanied by a brass band. The Manching plant is considered particularly vulnerable because it depends on future orders for the Eurofighter jet at a time when governments are reigning in their defense budgets. "We make a profit, we are working at full capacity," Stoerecker said. MARGINS TARGET EADS wants to streamline a collection of German, French and Spanish businesses that created the company in 2000, as part of plans to double margins to 10 percent by mid-decade and gain a global lift from Airbus, one of Europe's best-known brands. IG Metall has been critical of the focus on a firm margin target across the group, considering some of its businesses are more profitable than others, and warned that some managers could push back much-needed investments to hit the margin target in the short term. "Thanks to this self-indulgence, we and our families have to worry about our livelihood this Christmas," EADS Germany's works council chief Thomas Pretzl said at the Manching rally. IG Metall said it is prepared to negotiate with management but would not shy away from calling strikes if no agreement can be reached. It also urged politicians to help to protect jobs. "We understand the concerns of our workers," an EADS spokesman said, adding that the company is working on the details of its restructuring. He reiterated that the goal is to ensure that EADS retains its long-term competitiveness in the global defense and space business, even if significant cuts are required. The reorganization follows the company's decision this year to scrap a decades-old Franco-German ownership pact to reduce government interference and give management more freedom to reshape the group. (Additional reporting by Jan Schwartz and Reuters TV; Writing by Maria Sheahan; Editing by Jane Merriman and David Goodman)