Which type of airport lacks an operating control tower?

An uncontrolled airport is defined as an airport that does not have an operating control tower. At these airports, pilots communicate with each other and follow established procedures for takeoff, landing, and taxiing, but they do so without the guidance or instructions from air traffic controllers. This type of airport typically has fewer flight operations and is often used for general aviation purposes.

Controlled airports, on the other hand, have an operating control tower where air traffic controllers manage the flow of air traffic in and around the airport. Commercial airports, which serve scheduled air carrier operations, also fall under the category of controlled airports since they require coordinated management of higher traffic volumes. Private airports can be uncontrolled; however, they may also have control towers depending on their design and operational needs. Therefore, the distinct characteristic of an uncontrolled airport is the absence of a control tower, making option A clearly the accurate choice.