In 1896, newspapers throughout the United States began reporting accounts of mysterious airships flying overhead. Descriptions varied, but witnesses frequently invoked the century’s great technological achievements. Some sources reported dirigibles powered by steam engines. Others saw motorized, winged crafts with screw propellers. Many recalled a flying machine equipped with a powerful searchlight. As technologies of flight evolve, so do the descriptions of unidentified flying objects. The pattern has held in the 21st century as sightings of drone-like objects are reported, drawing concern from military and intelligence officials about possible security threats. While puzzling over the appearance of curious things overhead...