Class A Airspace – Generally, that airspace from 18,000 feet MSL up to and including FL600, including the airspace overlying the waters within 12 nautical miles of the coast of the 48 contiguous States and Alaska. Unless otherwise authorized, all persons must operate their aircraft under IFR.
See Also:
Class B Airspace
Class C Airspace
Class D Airspace
Class E Airspace
Class G Airspace
