Which type of airspace typically requires a clearance from air traffic control?

Class B airspace is the type that typically requires a clearance from air traffic control prior to entry. This airspace is usually found around major metropolitan areas and is designed to manage high-density traffic at lower altitudes, where many airlines and commercial flights operate.

Pilots must receive explicit clearance to enter Class B airspace to ensure safety and coordination with the sometimes heavy and complex air traffic in and out of these busy airports. The requirement for a clearance emphasizes the need for communication with air traffic control, which provides instructions and traffic advisories to maintain safe separation between aircraft.

In contrast, Class D does require communication with ATC but not necessarily a clearance, while Class E and Class G airspace do not require ATC clearance, allowing pilots to operate under less stringent regulations.