Which force opposes gravity during an aircraft's flight?

Lift is the force that opposes gravity during an aircraft's flight. It is generated by the wings of the aircraft as they interact with the oncoming air. When an aircraft moves forward, air flows over and under the wings, creating a difference in pressure that results in an upward force. This upward force must be greater than the weight of the aircraft (which is the force of gravity acting on it) for the aircraft to ascend or maintain altitude.

Understanding how lift operates involves concepts such as airflow and Bernoulli's principle, which explain how varying airspeed creates lower pressure above the wings and higher pressure below them. Thus, lift is crucial for overcoming the pull of gravity, allowing an aircraft to take off, climb, and sustain flight.