Sir George Cayley (1773-1857) was the first human to build a working heavier-than-air flying machine.
He spent about 54 years tryng to build a working glider, during which he documanted the aerodynamic forces of flight (Lift, Drag, and Thrust). At the age of 80 he finaly built one, and being too old and frail to fly it himself, he sent his coachman up instead. This flight made it 200 yards.

Cayley's succes was mostly due to his giving up on the idea that to acheive flight you need a lot of power, and instead focused on the aerodynamics involved in gliding.

He is also credited with the invention of the caterpillar tractor, automatic railroad crossing signals, the gradual combustion or furnace gas engine and self-righting lifeboats.