the flapping of the wings propel the bird forwards
A compressed C02 tank or High Pressure Air tank propels the paintball.
A plane flies forwards by exerting a force on the air with its wings. the air pushes back on those wings with an equal force that propels the bird forwards
The propeller.
The force of the jet engine propels a jet plane. The force of the engine pushes the exhaust gasses backward at great speed and the plane moves forward. This force propels the jet plane.
Propels it (moves it)
Air
It propels.
chemical reactions
Gravity
A jet engine usually propels an airplane. The jet engine propels the plane by ejecting extremely hot gasses out the back of the engines. Another way is by using huge fans to suck in air and blow it out the back.
Pseudostratified ciliated columnar epithelial tissue propels substances across surfaces.
energy