Which component of aerodynamic force allows an aircraft to stay in the air by opposing gravity?

Lift is the aerodynamic force that enables an aircraft to overcome gravity and remain airborne. It is generated by the movement of the aircraft through the air and is primarily influenced by the shape of the wings (airfoil) and the angle at which they meet the airflow, known as the angle of attack. When air moves over and under the wings, it creates a difference in pressure; lower pressure on top of the wing and higher pressure underneath. This pressure difference produces an upward force known as lift, which must be greater than the weight of the aircraft for it to ascend or stay aloft.

Thrust, while essential for propelling the aircraft forward, does not directly act against gravity as lift does. Drag is a force that opposes thrust and slows down the aircraft, and push is not a recognized aerodynamic force in the context of flight. Thus, lift is the correct answer, as it is the component specifically responsible for counteracting the effects of gravity.