As an aircraft climbs, what happens to the density of air?

As an aircraft climbs, the density of air decreases. This phenomenon occurs because air pressure and temperature typically decrease with altitude. As altitude increases, the weight of the air above diminishes, leading to lower air pressure and a resulting decrease in the number of air molecules per unit volume, which in turn reduces air density.

This change in density is significant for various aspects of flight, including lift generation, engine performance, and overall aircraft efficiency. Pilots and engineers must recognize this change, as it affects how an aircraft operates at different elevations, making it necessary to adjust flight plans and other operational parameters accordingly. Understanding this relationship between altitude and air density is essential for safe and effective flight operations.