What are the two primary forces acting on an aircraft during steady flight conditions?

In steady flight, an aircraft experiences two main sets of opposing forces: lift versus weight and thrust versus drag.

Lift is the upward force generated by the wings as air flows over them, counteracting the downward force of weight, which is the gravitational pull on the aircraft. For the aircraft to maintain altitude and achieve steady flight, lift must equal weight.

Simultaneously, thrust is the forward force produced by the engines, propelling the aircraft forward, while drag is the resistance against the aircraft's motion through the air. For steady flight, thrust must appropriately balance drag to allow for a constant speed.

Therefore, the combination of lift countering weight and thrust countering drag effectively describes the primary forces acting on an aircraft in a steady, level flight condition.