What happens to thrust and drag as altitude increases beyond 36,000 feet?

As altitude increases past 36,000 feet, several aerodynamic principles come into play, particularly related to engine performance and air density. Thrust produced by jet engines is largely influenced by the density of the air; as altitude increases, air density decreases, which leads to a reduction in engine performance. This means that jet engines produce less thrust at higher altitudes, especially as they operate closer to their maximum limits.

On the other hand, drag is primarily associated with the cross-sectional area of the aircraft and the airflow over the wings and fuselage, which is influenced by speed and altitude. While drag does not remain constant and can be affected by changes in speed and configuration, it generally does not increase at the same rate as thrust decreases with altitude. In fact, the decrease in air density can lead to a decrease in induced drag as the lift-to-drag ratio improves at higher altitudes.

This results in a scenario where thrust is decreasing at a faster rate than drag as altitude continues to rise beyond 36,000 feet. Thus, thrust decline outpaces the changes in drag, leading to a significant impact on aircraft performance.