Which device measures altitude during flight?

The device that measures altitude during flight is the altimeter. An altimeter functions by determining the altitude of an aircraft based on the atmospheric pressure changes that occur with variations in elevation. As an aircraft ascends, the air pressure decreases, which the altimeter reads and translates into an altitude measurement. This is crucial for pilots and drone operators to ensure they maintain proper flight levels and avoid obstacles.

While the airspeed meter is designed to measure the speed of the aircraft relative to the surrounding air, and a compass provides navigational information regarding direction, they do not offer altitude information. The Inertial Measurement Unit (IMU) is used to track the motion and orientation of a drone, but it does not directly measure altitude. Therefore, the altimeter stands out as the essential tool for measuring altitude in flight.