Air density is primarily influenced by temperature due to the ideal gas law, which describes the relationship between temperature, pressure, and volume of a gas. As the temperature increases, the kinetic energy of air molecules also increases, causing them to spread out more. This expansion results in a reduction in the density of the air because density is defined as mass per unit volume.
Conversely, cooler temperatures result in a decrease in the energy of air molecules, leading them to occupy a smaller volume and thereby increasing the overall air density. This phenomenon is crucial at altitude, where temperature changes can significantly affect the performance of aircraft. Warmer air at higher altitudes can lead to decreased lift and reduced engine performance due to the lower density.
Thus, higher temperatures indeed result in a decrease in air density, making the understanding of temperature's influence essential for pilots and aviation professionals in flight planning and performance calculations.