A second drone roughly the size of the Up Air quadcopter spun into action, buzzing like a mechanical wasp as it ascended to about 20 feet below its target. As it hovered, a crowd of Levin’s colleagues gathered around. A prompt appeared on-screen asking for permission to attack. Levin tapped a button, and the second drone, dubbed the Interceptor, shot upward, striking the Up Air One at 100 mph. The two aircraft somersaulted skyward briefly, then they plummeted back to earth and landed with two satisfying thuds.