What happens to Class D airspace when the control tower at the associated airport is inactive?

When the control tower at an airport is inactive, the Class D airspace associated with that airport is reclassified as Class E airspace. Class D airspace is specifically designed for airports with a control tower, where air traffic services (ATS) are provided. When the tower is not operational, the controlled nature of Class D airspace is lost, and the airspace transitions to Class E status.

Class E airspace is intended for various uses and can include areas where air traffic control does not provide separation between aircraft. This allows for more flexibility in operations, particularly when the airport is closed or when there is no active traffic for a period. Pilots are still expected to adhere to certain regulations and requirements applicable to Class E airspace, but the lack of an active control tower means that the stringent controls of Class D are no longer in place, thus allowing for more independent flight operations within that airspace.