The biggest trade war in history looks set to start today with the launch of a probe into alleged illegal aid for the world’s two aviation giants. The World Trade Organisation will be acting as referee in this battle which pits US firm Boeing against Europe’s Airbus. Two panels have been set up to investigate twin accusations by Brussels and Washington that the world’s two largest civil aircraft makers received billions of euros’ worth in funding in violation of trade rules. It was the US which initiated the dispute when it complained that Airbus was receiving massive assistance from the European Union, including 5.5 billion euros in subsidies for its new A380 superjumbo jet. Airbus overtook Boeing as the world’s largest commercial aircraft maker in 2003. In a tit-for-tat reaction, the European aviation giant said Boeing had benefited from even larger amounts in the form of grants from Washington state and in US defence contracts.