British PM May welcomes Bombardier's trade victory over Boeing

The dispute between the two companies had put thousands of jobs at risk in Belfast, Northern Ireland, where Bombardier makes the CSeries CS100 and CS300 carbon wings.

"I welcome this decision, which is good news for British industry," May said on Twitter. "Bombardier and its innovative workforce play a vital role in the Northern Ireland economy."

Britain's business minister, Greg Clark, also welcomed the news, saying in a statement that the British and Canadian governments had maintained all along that the case was unjustified.

"This is excellent news for the dedicated workforce in Northern Ireland and supply chain across the UK, who have a great future ahead," he said.

"The decision by the International Trade Commission confirms what the UK and Canadian Governments working hand in hand has maintained from the outset, that this case is unjustified. We are pleased that the ITC have now recognized this."

The U.S. International Trade Commission voted 4-0 to reject Boeing's claims that it suffered injury by Bombardier underpricing the CSeries in the U.S. market and discarded a Commerce Department recommendation to slap a near 300-percent duty on sales of the 110-to-130-seat jets for five years.

(Reporting by Shalini Nagarajan in Bengaluru and Kate Holton in London; Editing by Alison Williams)