Authorities investigating a series of possible jetpack sightings over Los Angeles believe they may have identified an explanation for the mysterious reports - one that requires no fuel, no engines, and no high-flying technology. "One working theory is that pilots might have seen balloons," the Federal Bureau of Investigation and Federal Aviation Administration said in statements, after NBC Los Angeles obtained police video and photos that appear to show a human-shaped inflatable toy floating thousands of feet above Beverly Hills. The crew aboard an LAPD helicopter captured the images last year, about two weeks after the second reported sighting of...