"The Commission is starting preparations so that the EU can promptly take action based on the arbitrator's decision on retaliation rights in this (Boeing) case," a Commission spokesman said.

"The European Union remains open for discussions with the United States, provided these are without preconditions and aim at a fair outcome," he continued.

(Reporting by Philip Blenkinsop; editing by Foo Yun Chee)

Stocks treated in this article : Airbus SE, Boeing Company (The)