What effect does altitude have on the stall speed of an airplane?

The relationship between altitude and stall speed is nuanced. Stall speed is the minimum speed at which an aircraft must fly to maintain controlled flight. Stall speed is affected by factors like weight, load factor, and air density.

As altitude increases, air density decreases. This reduction in air density does indeed lead to a decrease in the airfoil's lift. However, it is essential to note that stall speed itself, which is a function of weight and wing design, doesn't inherently change due to altitude alone. The stall speed is typically expressed as a function of the square root of the lift-to-weight ratio. Since weight remains constant regardless of altitude, the basic stall speed in terms of true airspeed does not increase simply because the aircraft is at a higher altitude. Rather, the stall speed expressed in indicated airspeed may appear to increase due to the lower density altitude, but true stall speed remains consistent.

In summary, stall speed does not increase with altitude in the way that option A suggests. It is also inaccurate to state that it has no effect at all, as the environmental factors at different altitudes can influence performance; however, the pure stall speed in terms of the physics of lift and weight does not change directly with altitude in a fundamental sense. Thus,