Britain's newest aircraft carrier, HMS Queen Elizabeth, is helping to take on the “lion’s share” of operations against theIslamic State group in Iraq, U.K. naval commanders said. It has also piqued the interest of Russian warplanes, who try to keep tabs on its cutting-edge F-35 jet in a “cat-and-mouse” game with British and U.S. pilots. Speaking aboard the 65,000-ton carrier on its first-ever deployment, Commodore Steve Moorhouse said the U.K. is carrying out most of the missions to wipe out the remnants of IS in Iraq as the U.S. focuses on its withdrawal from Afghanistan. “At the moment, we’r...