True Airspeed (TAS)

The actual speed of the aircraft through the air mass, corrected for altitude and temperature effects on air density. TAS is derived by correcting calibrated airspeed for the difference between actual air density and standard sea-level density. At higher altitudes where the air is thinner, TAS is higher than indicated airspeed for the same aerodynamic conditions. TAS is used for flight planning calculations such as groundspeed, fuel burn, and estimated time en route because it represents the aircraft's true performance through the atmosphere.