Airspace (Class A, B, C, D, E, G)

The National Airspace System (NAS) is divided into six classes that define communication, equipment, and weather requirements for flight. Controlled airspace (Classes A through E) requires some level of ATC interaction, while uncontrolled airspace (Class G) does not. Understanding airspace is essential for every pilot because entry requirements, visibility minimums, and cloud clearance rules vary by class.