In aviation, V-speeds are standard terms used to define airspeeds important or useful to the operation of all aircraft. These speeds are derived from data obtained by aircraft designers and manufacturers during flight testing for aircraft type-certification. Using them is considered a best practice to maximize aviation safety, aircraft performance, or both.

In aviation, airspeed is the speed of an aircraft relative to the air it is flying through. It is difficult to measure the exact airspeed of the aircraft, but other measures of airspeed, such as indicated airspeed and Mach number give useful information about the capabilities and limitations of airplane performance. The common measures of airspeed are:Indicated airspeed (IAS), what is read on an airspeed gauge connected to a pitot-static system. Calibrated airspeed (CAS), indicated airspeed adjusted for pitot system position and installation error. True airspeed (TAS) is the actual speed the airplane is moving through the air. In conjunction with winds aloft it is used for navigation. Equivalent airspeed (EAS) is true airspeed times root density ratio. It is a useful way of calculating aerodynamic loads and airplane performance at low speeds when the flow can be considered incompressible. Mach number is a measure of how fast the airplane is flying relative to the speed of sound.