The World Trade Organization gave the EU approval to levy tariffs on $4B of US goods in response to subsidies received by Boeing. The ruling follows a similar decision last year (made in the US’ favor), in which the WTO allowed the US to levy tariffs on $7.5B of EU goods in response to subsidies received by Airbus.
More context: The 16-year Boeing-Airbus dispute is the longest and largest corporate trade dispute managed by the WTO.