Comes from air flowing around the wings. Speed, angle of attack, and flaps change how strongly the wing redirects air.
Effect More lift than weight makes the aircraft climb; less makes it descend.
Comes from gravity pulling the aircraft’s mass towards Earth. It acts through the centre of gravity.
Effect Weight opposes lift. It stays fixed here because the aircraft’s mass does not change.
Comes from the engines accelerating air backwards, which pushes the aircraft forwards.
Effect More thrust than drag accelerates the aircraft and helps it gain airspeed.
Comes from air resisting the aircraft. It rises with speed, lift demand, and extended flaps.
Effect Drag opposes thrust, slowing the aircraft when it becomes the stronger force.