PBS
Pbs Learning Media: Pilotless Flight: Timeline of Unmanned Aerial Vehicles
Explore this NOVA: "Spies That Fly" interactive timeline and discover the many technological innovations in the history of unmanned flight, from hot-air balloons to miniature flying robots.
NASA
Nasa: Robin Whirlybird on Her Rotorcraft Adventures
Read (or listen to) the illustrated story of Robin, who goes to work with her mother who works at a rotorcraft research center. Includes many interactive supplemental activities.