Final answer:
The maximum speed with flaps fully extended is determined by the aircraft's manufacturer and specified in the aircraft's flight manual.
Step-by-step explanation:
An airspeed indicator is used in aircraft to measure the speed of an aircraft relative to the air. It is not directly related to the maximum speed with flaps fully extended. The maximum speed with flaps fully extended is determined by the aircraft's manufacturer and is specified in the aircraft's flight manual. The manufacturer takes into account various factors such as the aircraft's design, structural limits, and operational considerations to determine the maximum speed with flaps fully extended.