Which instrument displays the speed of an aircraft?

The airspeed indicator is the instrument specifically designed to display the speed of an aircraft. It measures the dynamic pressure of the air flowing around the aircraft and converts that information into a visual representation of the current airspeed, typically indicated in knots or miles per hour. This crucial data helps pilots understand how their aircraft is performing in relation to aerodynamic limits, enabling safe and efficient operation during various phases of flight, such as takeoff, cruise, and landing.

In contrast, the vertical speed indicator shows the rate of climb or descent, giving pilots valuable information about altitude change over time. The attitude indicator reflects the aircraft's orientation relative to the horizon, indicating whether the wings are level or if the plane is climbing/descending. The turn coordinator shows the rate of turn and helps pilots maintain coordinated flight, but none of these instruments provide direct information on the aircraft's speed. Hence, the airspeed indicator is the correct choice for displaying speed.