Measured in feet. According to the relevant information of the forum, the height unit of the civil aviation contact tower is feet, which is converted into meters, and the cruising altitude of civil aviation is 1000 meters. Tower is an air transport control facility installed in the airport to control the take-off and landing of aircraft. The tower is the tallest building in the airport, and the 360-degree glass house on the top floor is the symbol. In this glass house, air traffic controllers should pay close attention to the status of every plane in the airport.