The two categories of airspace are: regulatory and non-regulatory. Within these two categories there are four types: controlled, uncontrolled, special use, and other airspace. Controlled airspace is a generic term that covers the different classifications of airspace and defined dimensions within which air traffic control (ATC) service is provided in accordance with the airspace classification. Uncontrolled airspace is not controlled by the ATC, but pilots should remember there the visual flight rules (VFR) minimums and comply them. Special use airspace is the designation for airspace in which certain activities must be confined, or where limitations may be imposed on aircraft operations that are not part of those activities.
Aeronautical Chart User's Guide Airspace Chart Page 50 & 51
AIM Ch-03 Airspace
PHAK Ch-15 Airspace
91.126 Operating on or in the vicinity of an airport in Class G airspace
91.127 Operating on or in the vicinity of an airport in Class E airspace
91.129 Operations in Class D airspace
91.130 Operations in Class C airspace
91.131 Operations in Class B airspace
91.133 Restricted and prohibited areas
91.135 Operations in Class A airspace
91.155 Basic VFR weather minimums
91.157 Special VFR weather minimums
Private Pilot ACS Page 7 Task E. National Airspace System