Class A airspace. Controlled airspace within which only IFR flights are permitted. Airspace designated from the base of all controlled high level airspace up to and including FL 600.
Class B airspace. Controlled airspace within which only IFR and Controlled VFR (CVFR) flights are permitted. Includes all controlled low level airspace above 12,500 feet ASL or at and above the minimum en route IFR altitude, (whichever is higher) up to but not including 18,000 feet ASL. ATC procedures pertinent to IFR flights must be applied to CVFR aircraft.
NOTE: The CVFR pilot is responsible to maintain VFR flight and visual reference to the ground at all times.
Class C airspace. Controlled airspace within which both IFR and VFR flights are permitted, but VFR flights require a clearance from ATC to enter.
Class D airspace. Controlled airspace within which both IFR and VFR flights are permitted, but VFR flights do not require a clearance from ATC to enter, however, they must establish two-way communications with the appropriate ATC agency prior to entering the airspace.
Class E airspace. Airspace within which both IFR and VFR flights are permitted, but for VFR flight there are no special requirements.
Class F airspace. Airspace of defined dimensions within which activities must be confined because of their nature, or within which limitations are imposed upon aircraft operations that are not a part of those activities, or both. Special use airspace may be classified as Class F advisory or Class F restricted.
Class G airspace. Uncontrolled airspace within which ATC has neither the authority nor responsibility for exercising control over air traffic.