What opposes the rearward retarding force of airplane drag?

Thrust is the force generated by the airplane’s engines that propels it forward. It acts in the opposite direction to drag, which is the retarding force experienced by the airplane as it moves through the air. While weight and gravity contribute to the overall forces acting on an airplane, they are associated with vertical movement and stability rather than opposing drag. Lift is also a vertical force that supports the airplane in the air, but it does not counteract drag. Therefore, thrust is the correct answer, as it directly opposes the effects of drag, allowing the airplane to maintain or increase its speed during flight. This dynamic is essential for achieving a balance of forces during takeoff, cruising, and landing.