Gravity , wind and air pressure.
four
gravity
Thrust and drag are two important forces act on air craft.
Lift, weight, thrust and drag.
Forces, these forces can be created by the environment or the airplane.
There are four forces that act on an airplane that keeps it at a level altitude. Thrust, drag, weight, and lift determine whether a pilot flies at a level altitude.
The center of gravity is a point on the airplane that the airplane would balance while sitting on the ground. The center of gravity or also called "the CG" is important in trimming the aircraft in flight as the weight has to balance out the forces on the wing. It is also important in aerodynamic maneuvers as the G-forces act through CG.
There are two forces that causes an airplane to be airborne. They are Thrust and Lift. The other two forces resists the airplane's flight. They are Gravity and Drag.
the forces are equal to balance the aircraft in flight
"Thrust" is a force, referenced to the direction in which the aircraft is pointing. Take all the forces that act on the airplane. For each one, find the magnitude of its component in the direction in which the airplane's nose points. Their sum is the "thrust" at that moment.
Gravity, force and lift are all forces that cause an airplane to fly. There are more forces depending on what time of airplane is in flight. For example the forces used to keep a comerical jet as to a fighter or military jet. As there are many forces the same the proportion is different there for the air flow if different on each airplane.
Drag is a force that acts opposite to the direction of movement of an airplane. Drag is mainly caused by air. The other forces that act on the plane while moving in the air are thrust, lift etc..