How does increased altitude generally affect aircraft performance?

Increased altitude generally leads to a decrease in aircraft performance due to the thinning of the air. As altitude increases, the air density drops, which directly affects various performance aspects of an aircraft.

Specifically, thinner air results in decreased lift generated by the wings, as lift is a function of air density, wing area, and airspeed. Additionally, engines, particularly piston engines, rely on air to produce power; with less air available, engine performance can be diminished. Even turbocharged engines may not operate at peak efficiency at higher altitudes if they are unable to maintain their boost levels.

Furthermore, the reduction in air density impacts the aircraft's ability to generate sufficient thrust, often requiring higher indicated airspeeds to achieve the same aerodynamic effects as at lower altitudes. Overall, these factors contribute to a decline in climb rate, climb performance, and overall aircraft capabilities when operating at higher altitudes.