Cayley's helicopter from "On Aerial Navigation.

Credit - Gary Bradshaw; "To Fly Is Everything"

George Cayley's design for an aerial carriage.

Credit - "(c) 2001 National Air and Space Museum, Smithsonian Institution (SI Neg. No. 92-14966)"

Cayley's 1853 glider.

Credit - Wright State University

Cayley's 1799 design of an aircraft.

Credit - Wright State University

Cayley's 1804 glider design.

Credit - Wright State University

Cayley's 1809 glider design.

Credit - Gary Bradshaw; "To Fly Is Everything"

Cayley's gliding bird from "On Aerial Navigation"

Credit - Gary Bradshaw; "To Fly Is Everything"

Cayley's 1849 glider.

Credit - Wright State University

Cayley's gliders.

Credit - "(c) 2001 National Air and Space Museum, Smithsonian Institution (SI Neg. No. 85-18307)"