How does lower density air affect aircraft performance?

Lower density air negatively impacts aircraft performance by reducing power, thrust, and lift. In lower density environments, such as at higher altitudes, there are fewer air molecules available for the aircraft's engines to draw in for combustion or for the wings to generate lift.

This reduction in air density leads to a decrease in engine performance as there is less oxygen available, which results in lower thrust capability. Additionally, the wings are unable to generate as much lift due to the diminished air pressure over and under the wing. This results in the aircraft requiring higher speeds to maintain the necessary lift. Overall, the combined effects of reduced engine performance and decreased lift manifest as a reduction in the overall performance of the aircraft in these conditions.

In contrast, the other choices suggest either an improvement or no effect on performance, which does not align with the principles of aerodynamics and engine performance in lower density air.