Above the South China Sea (CNN)The Chinese navy issued warnings eight times as a U.S. surveillance plane on Wednesday swooped over islands that Beijing is using to extend its zone of influence. Seeking to further challenge China's military build-up in the South China Sea, the plane conducted a reconnaissance mission over a contested military installation being constructed on a manmade series of islands. A CNN team was given exclusive access to fly onboard the P8-A Poseidon, America's most advanced surveillance and submarine-hunting aircraft, as it flew over the islands. READ: China cautions U.S. Navy on patrols The U.S. is considering...