What is meant by uncontrolled airspace?

Uncontrolled airspace refers to airspace where there are no air traffic control (ATC) services provided to aircraft. In this type of airspace, pilots are responsible for their own navigation and separation from other aircraft. This enables greater flexibility for pilots, as they are not subject to the same level of regulation as in controlled airspace. Pilots must maintain communication with ATC if they wish to enter controlled airspace, but in uncontrolled spaces, they operate largely on their own judgment, following established rules and regulations.

The other options describe different classifications or restrictions of airspace that do not align with the definition of uncontrolled airspace. For instance, airspace limited to IFR (Instrument Flight Rules) flights or dedicated to specific military operations involves controlled environments where ATC plays a crucial role in managing traffic and ensuring safety, which is contrary to the concept of uncontrolled airspace. Similarly, airspace designated solely for controlled airspace contradicts the definition, as it implies that ATC services are indeed being provided.