What is the difference between true airspeed and indicated airspeed?

True airspeed refers to the actual speed of the aircraft relative to the surrounding air, which is crucial for understanding the aircraft's performance and navigation. This measure takes into account the altitude and temperature, which affect air density. As an aircraft climbs, the air becomes less dense; therefore, the same indicated airspeed does not equate to the same true airspeed at different altitudes due to changes in air density.

Indicated airspeed, on the other hand, is what is directly shown on the airspeed indicator in the cockpit. It does not compensate for variations in air density caused by altitude or temperature. Therefore, using true airspeed provides a more accurate measure of the aircraft's performance in the air, particularly for flight planning and navigation, while indicated airspeed is primarily used during flight for maintaining safe operating conditions and procedures.

Understanding the distinction between these two types of airspeed is critical for pilots as it influences decisions regarding performance, fuel consumption, and operational safety.