What happens to the performance of a small unmanned aircraft as high-density altitude decreases?

As high-density altitude decreases, the performance of a small unmanned aircraft increases due to a combination of factors related to air density and engine efficiency. At lower altitudes or in conditions where density altitude is reduced, the air is denser, which positively impacts the aircraft's ability to generate lift.

Specifically, denser air provides more oxygen for combustion in the engine, improving power output. Additionally, greater air density enhances lift generated by the wings, allowing the aircraft to perform better in terms of climb rate, maneuverability, and overall efficiency.

This change in performance is particularly noticeable in terms of reduced takeoff distances and enhanced endurance, as the aircraft can operate more efficiently. In contrast, as density altitude increases, which often occurs in hot temperatures or at high elevations, aircraft performance is hindered, leading to reduced power and lift.

Thus, the correct answer emphasizes the performance benefits experienced by small unmanned aircraft when operating in conditions of lower density altitude.