Originally developed in the early 20th century for military purposes, unmanned aircraft, or drones, have come to be used for a variety of purposes.Readers (Grades 3-5) will find out how drones work and what it takes to pilot them. They will also learn why the use of drones has become a controversial issue, how unmanned aircraft have been improved over time, and what today's engineering innovators are planning for the future of drone technology.