What is the force that acts opposite to weight or gravity?

The force that acts opposite to weight or gravity is lift. Lift is the aerodynamic force that allows an object, like an airplane, to rise off the ground and is primarily generated by the motion of the object through the air. When an aircraft's wings are designed appropriately and the aircraft moves forward, the shape of the wings creates a difference in air pressure above and below the wings, resulting in lift that acts upward, opposing the downward force of gravity.

In contrast, thrust is the forward force produced by the engines, and drag is the resistance force that opposes thrust and is also produced by air friction. While weight is the gravitational force acting downward on an object, it is lift that counteracts this force, enabling flight. Therefore, lift is the correct answer, as it serves the crucial function of opposing the force of gravity acting on the aircraft.