What happens to thrust during straight and level flight at constant speed?

In straight and level flight at constant speed, the forces acting on the aircraft must be balanced for the aircraft to maintain its altitude and speed. Thrust is the forward force produced by the engines, while drag is the resistance experienced by the aircraft due to air friction and aerodynamic shapes.

When an aircraft is flying at constant speed, the thrust produced by the engines is equal to the drag opposing the aircraft's forward motion. This balance of forces allows the aircraft to travel steadily without acceleration or deceleration. If thrust were greater than drag, the aircraft would accelerate, and if it were less than drag, the aircraft would decelerate. Therefore, for straight and level flight at constant speed, it is essential that thrust equals drag, ensuring stable flight dynamics.

This principle is fundamental in understanding not just the mechanics of flight, but also the relationships between thrust, drag, and the overall performance of the aircraft.