Exclusive - U.S. set to approve international debut of F-35 fighter: sources

WASHINGTON (Reuters) - The U.S. Defense Department is poised to approve the first trans-Atlantic flight of Lockheed Martin Corp's F-35 fighter jet in July, when the new warplane is expected to take part in two international air shows near London, according to multiple sources familiar with the issue.

U.S. Defense Secretary Chuck Hagel is "very close" to a decision that would allow two or three F-35s to fly at the Royal International Air Tattoo (RIAT), an annual military air show held outside London, and the larger Farnborough air show, held every two years, said the sources, who were not authorized to speak publicly.

Britain, which contributed $2 billion (1.2 billion pounds) to the development of the new radar-evading fighter jet and plans to buy 138 F-35s in coming years, asked for the jet's participation to help showcase the increasing maturity of the new radar-evading plane. Britain was also the first international partner on the program.

(Reporting by Andrea Shalal; Editing by Ros Krasny and Sandra Maler)