Stall speed is the minimum _____ required to maintain level flight at CLMAX AOA.

Stall speed refers to the minimum speed at which an aircraft can maintain level flight before airflow over the wings becomes insufficient to provide the necessary lift. This speed is specifically associated with a critical angle of attack, known as CLMAX, at which the maximum lift coefficient is achieved.

True airspeed is the actual speed of the aircraft through the air and is relevant when discussing stall speed at a given angle of attack. As altitude increases, air density decreases, and therefore, true airspeed increases for the same indicated airspeed. For pilots and aerodynamicists, understanding stall speed in terms of true airspeed is crucial, especially during flight planning and performance calculations.

Indicated airspeed, calibrated airspeed, and equivalent airspeed are all related to flight dynamics but are affected by factors like altitude, air temperature, and instrument errors. When discussing stall speed in the context of maintaining level flight, true airspeed provides the most accurate reflection of the aircraft's performance under various atmospheric conditions, making it the correct choice in this scenario.