What airspace is typically controlled by air traffic control?

Class B, C, and D airspace are types of controlled airspace where air traffic control (ATC) services are provided. In these areas, ATC is responsible for managing the flow of aircraft to ensure safety and efficiency, especially in locations where there is heavy air traffic or near busy airports.

Class B airspace surrounds the nation's busiest airports and requires clearance from ATC for entry, ensuring that aircraft operate safely within the high volume of air traffic. Class C airspace, typically found at airports with a moderate amount of traffic, also requires communication with ATC, and pilots must establish two-way radio communication before entering. Class D airspace is associated with airports that have an operating control tower, where ATC provides instructions for arriving and departing aircraft.

Uncontrolled airspace, as suggested in one of the other options, does not have ATC oversight; pilots operate under visual flight rules (VFR) without the requirement to communicate with ATC, which can lead to a different set of operational considerations. Similarly, Class G airspace is also uncontrolled and typically extends from the surface up to the base of the overlying controlled airspace, where pilots fly without ATC direction.

The idea that control is limited to only at airports lacks