aircraft, but instead have a maximum operating speed expressed in knots, V_MO and Mach number, M_MO. Thus, a pilot of a jet aeroplane needs both an airspeed indicator and a Machmeter, with appropriate red lines. An ASI will include a red-and-white striped pointer, or "barber's pole", that automatically moves to indicate the applicable speed limit at any given time.

Angle of attack and Lift Reserve Indicators