How is Class B airspace characterized?

Class B airspace is indeed characterized by its typical location surrounding the busiest airports, where a high volume of air traffic is present. This airspace is established to manage the complexities of flight operations in these areas effectively. Pilots must obtain specific clearance from air traffic control to enter Class B airspace, ensuring that the air traffic in and out of the airport is organized and safe.

This requirement for clearance is crucial because of the potential for collision with commercial traffic, which can have serious implications for safety. The structure of Class B airspace often resembles an upside-down wedding cake, with different layers at various altitude levels to help manage the flow of air traffic.

In contrast, the other options describe characteristics that do not apply to Class B airspace. For instance, Class B is not defined by being over sparsely populated areas or being uncontrolled; in fact, Class B is controlled airspace with strict communication requirements. Additionally, Class B airspace is not designated solely for military flights, as it accommodates all types of flights provided they comply with the regulations set for that airspace.