For millennia, would-be aviators knew bird flight had something to do with wing structure. As it turns out, the shape of a wing is optimised to generate lift, an upward force caused by manipulating airflow. A wing has a rounded leading edge with a slight upward tilt, a curved topside, and a tapered trailing edge pointing downward. This shape alters the flow of air molecules into a downward trajectory. This results in – as Newton put it in his Third Law of Motion – “an equal and opposite reaction.” When the wing pushes the air molecules down, the molecules push the wing up with equal force. The airflow also creates a lower pressure area above the wing, which sucks the wing up.
Constructing wings is the easy part. To fly, you need to generate enough forward force – or thrust – to produce the necessary lift to counteract gravity. The Wright Brothers accomplished this by linking a piston engine to twin propellers. A plane propeller is simply a group of rotating wings shifted 90 degrees, so the direction of lift is forwards rather than upwards. In 1944, engineers upgraded to jet engines, which produce much greater thrust by igniting a mixture of air and fuel, and expelling hot gasses backward.
A pilot controls a plane by adjusting movable surfaces on the main wings, as well as smaller surfaces and a wing-like rudder on the tail. By changing the shape and position of these structures, the pilot varies the lift force, acting on the different ends of the plane to essentially pivot the plane along three axes: its pitch (up or down tilt of the nose), roll (side to side rotation), and yaw (turn to the left or right).
Engineers keep planes as light and aerodynamic as possible. Modern fighter jets are manufactured from super-strong, lightweight composite material, applied in layers to form precise, aerodynamic shapes.