Ground observers across an increasing number of U.S. states are reporting aircraft in the sky that appear to be unmanned aerial systems (UAS), or drones, leaving the public on edge. With no definitive answers available, aviation experts—perplexed by the federal government’s limited response—suggest multiple origins for the unidentified aircraft. During weeks of sightings pooling out of states such as New Jersey, Pennsylvania, New York, Maryland, Virginia, Massachusetts, California, Ohio, and Utah, some observers reported seeing aircraft as large as SUVs. Now, state and local officials are demanding answers from Washington. A Dec. 17 joint statement released by the Department of Homeland Security, the FBI, the Federal Aviation Administration (FAA), and the Department of Defense confirmed more than 5,000 reported drone sightings in the past few weeks, “with approximately 100 leads generated.”…