For the first time in history, American F-35 Joint Strike Fighters had at least one close encounter with China’s 5th-generation J-20 over the Pacific, and the response from Air Force officials has been somewhat mixed.While the commander of Pacific Air Forces described the Chinese fighter itself as “nothing to lose sleep over,” he qualified his dismissive statements with positive observations about how Chinese forces are operating their first stealth aircraft.Here’s everything you need to know.