The European Union (EU) will impose tariffs on up to $4 billion of US imports in retaliation for US subsidies for Boeing, but have said that it was hopeful of an improvement in trade ties under U.S. President-elect Joe Biden. The decision was given the green light by the World Trade Organization last month and represents the latest in a 16-year US-EU dispute over civil aviation subsidies. Starting earlier this week, the EU will impose tariffs of 15% on US exports of planes and parts and of 25% on a range products including tobacco, nuts, fruit juice, fish, spirits, bags, tractors and casino and gym equipment. The bloc says its main objective is to persuade the United States to negotiate a solution.