In this Tuesday, May 21, 2019 photo, a drone flies over downtown Reno, Nev., before landing on the Cal-Neva casino parking garage, as part of a NASA simulation to test emerging technology that someday will be used to manage travel of hundreds of thousands of commercial, unmanned aerial vehicles (UAVs) delivering packages. It marked the first time such tests have been conducted in an urban setting. (AP Photo/Scott Sonner)