Definition
Controlled airspace surrounding the nation's busiest airports, generally from the surface up to 10,000 feet MSL, shaped like an upside-down wedding cake with multiple layered shelves tailored to each airport. An ATC clearance is required to enter, operate within, or transit Class B airspace, and all aircraft inside receive separation services from controllers. Pilots must hold at least a private pilot certificate (or a student pilot certificate with specific endorsements) and the aircraft must have an operable two-way radio, an operable transponder with Mode C, and ADS-B Out.
Plain English
The protected, tightly controlled airspace wrapped around the country's busiest airports. You cannot enter it without permission from air traffic control, and your aircraft needs the right equipment to be there.
Context Anchor
Seen on aviation charts and in flight planning near major airports, and heard during radio communication with ATC before entering busy airport areas.
Derivation
The FAA classifies airspace using letters A through G, with Class A being the most restrictive controlled airspace and Class G being uncontrolled. Class B sits near the top of the controlled tier because it surrounds high-traffic airports where strict separation is essential. The 'B' is simply a position in the alphabet-based system, not an abbreviation.
Why Pilots Care
Entry requires ATC clearance, continuous radio contact, and a transponder; unauthorized entry can lead to enforcement action.
Analogy
Picture an upside-down wedding cake sitting over a busy airport: the smallest layer is on the ground at the airport itself, and each layer above gets wider as you go up. Each layer is a piece of Class B airspace, and you need permission to be inside any of them.
Intuition Check
Class B does not mean the airport is second-best or that the airspace is only for airline pilots. It means this area has a specific set of FAA entry rules, and the key rule is that you need a clear ATC clearance before entering.
Example Sentence 1
Before flying through the Class B airspace over Dallas-Fort Worth, the student pilot called Approach and waited for the controller to say 'cleared into the Class Bravo.'
Example Sentence 2
Reviewing the chart helped the pilot locate the outer boundaries of Class B airspace before departure.