GlossaryAirspace
AirspaceClass B Airspace
Also: Class B, Bravo airspace
The controlled airspace around the busiest airports, shaped like an upside-down wedding cake, that requires an ATC clearance before you enter.
“Class B airspace is generally airspace from the surface to 10,000 feet MSL surrounding the nation’s busiest airports in terms of airport operations or passenger enplanements.”
Related terms