Class B Airspace

The most restrictive controlled airspace surrounding the nation's busiest airports (e.g., LAX, JFK, ORD), depicted on sectional charts as solid blue lines in an upside-down wedding cake shape. Pilots must receive explicit ATC clearance to enter, must have a Mode C transponder, and VFR flight requires 3 SM visibility and clear of clouds. Student pilots need a specific instructor endorsement to operate in or through Class B airspace at certain airports.