Which form of airspeed takes into account nonstandard temperature and pressure?

True airspeed is the correct answer because it represents the actual speed of an aircraft relative to the mass of air through which it is moving. It takes into account the nonstandard temperature and pressure conditions of the atmosphere, which can affect an aircraft's performance and speed readings.

While indicated airspeed is the reading shown on the airspeed indicator in the cockpit, it does not consider altitude or temperature corrections, and therefore remains affected by local pressure and temperature conditions. Calibrated airspeed adjusts indicated airspeed for instrument and installation errors but still does not account for variations in temperature and pressure. Equivalent airspeed is adjusted for compressibility effects at higher speeds but also does not factor in variations from standard conditions.

In contrast, true airspeed is essential for navigation and flight planning as it provides pilots with a more accurate representation of their performance in the current atmospheric conditions.