Figure 2 shows the four forces of thrust, weight, drag, and lift and how they act on an airplane. Objects that move through the air must take into account each of these forces. According to Newton's second law, if we want an object in air to move forward and up, then the lifting force must be larger than the weight, and the thrust force must be larger than the drag. Four forces of flight Thrust is usually provided by some type of engine or launching assemblage. The launching apparatus is not necessarily part of the flying system.
Gravity force is simply the weight of the flying system.
Gravity forces are proportional to the amount of material needed to construct an object. The more materials and heavier those materials, the more a flying system will weigh. Drag and lift force result from the flow of air over the object. Lifting force induced by air flow over arched wing section. Aerodynamic lift is the force that enables aircraft to stay in the air.