How is "controlled airspace" defined?

The definition of "controlled airspace" designates it as the area where air traffic control (ATC) is responsible for the management of traffic and the separation of aircraft. This involvement of ATC ensures that the operations within that airspace are conducted safely, efficiently, and in an organized manner. Pilots flying in controlled airspace are required to establish communication with ATC, follow their instructions, and often file flight plans. This structure is essential for maintaining the safety of all aircraft operating in this busy airspace, particularly in areas with a high volume of air traffic or near airports.

In contrast, the other options imply different concepts. The notion of airspace without traffic control denotes uncontrolled airspace, where pilots operate without ATC intervention. The idea that pilots have complete control suggests a lack of structure and oversight, which is contrary to the nature of controlled airspace. Lastly, restricting airspace only to military flights does not accurately represent controlled airspace, as it includes both military and civilian aircraft, provided that they comply with ATC regulations.