When you drive a car, you can only steer right or left, but
when you fly a plane, you can turn right or left, and also
up and down. This makes steering a plane pretty complicated.
Scientists and pilots call movements up and down as "pitch"
and movements left and right as "yaw." Often in
order to make a turn, a pilot will actually roll the plane
sideways as well as turn the plane's nose in a new direction.
Early gliders crashed often because the pilots tried to steer
with just their body weight. Unlike cars, most planes today
can fly tipped sideways, and some can even fly upside down!
Wilbur came up with many of his flying ideas by watching buzzards
soar along the cliffs of the Great Miami River in Dayton,
Ohio. Wilbur noticed how the birds adjusted their direction
by changing the shape and position of their wings. To make
a turn, the birds would turn one wing tip up and one wing
tip down. Wilbur went home and experimented by twisting a
long, thin cardboard box the same way.