What role does thrust play in an aircraft's flight?

Thrust is a crucial aerodynamic force that propels an aircraft forward and overcomes drag, which is the resistance the aircraft experiences as it moves through the air. When the engines produce thrust, it allows the airplane to accelerate and maintain its speed in level flight. This forward motion is essential for generating lift, as the wings must have sufficient airflow over them to create the pressure difference needed to rise in the air.

In level flight, thrust must be equal to drag for the aircraft to maintain a constant speed. If thrust exceeds drag, the aircraft accelerates. Conversely, if drag exceeds thrust, the plane will decelerate. Thus, thrust does not only play a role in increasing altitude but is fundamental for the overall performance of the aircraft throughout all phases of flight, including takeoff, cruising, and landing.