Airspace means the portion of the atmosphere controlled by a particular country on top of its territory and territorial waters or, more generally, any specific three-dimensional portion of the atmosphere. A territory (from the word terra, meaning land) is a defined area (including land and waters), usually considered to be a possession of an animal, person, organization, or institution. ... Map of Sealand and the United Kingdom, with territorial water claims of 3nm and 12nm shown. ...

Airspace is divided into two basic types:

• Controlled airspace exists where it is deemend necessary that air traffic control has some form of positive executive control over aircraft flying in that airspace.

• Uncontrolled airspace is airspace in which air traffic control does not exert any executive authority, although it may act in an advisory manner.

Airspace may be further subdivided into a variety of areas and zones, including zones where there are either restrictions on flying activities or complete prohibition of flying activities. Controlled airspace exists in areas where air traffic control is capable of providing traffic separation. ... Air Traffic Control Towers (ATCTs) at Amsterdams Schiphol Airport (Netherlands) Air traffic control (ATC) is a service provided by ground-based controllers who direct aircraft on the ground and in the air. ... Uncontrolled airspace exists wherever a control service cant be provided for whatever reason, or is not deemed necessary, many of them are above mountains or oceans. ... Air Traffic Control Towers (ATCTs) at Amsterdams Schiphol Airport (Netherlands) Air traffic control (ATC) is a service provided by ground-based controllers who direct aircraft on the ground and in the air. ...

By international law, the notion of a country's sovereign airspace corresponds with the maritime definition of territorial waters as being 12 miles out from a nation's coastline. Airspace not within any country's territorial limit is considered international, analogous to the "high seas" in maritime law. However, a country may, by international agreement, assume responsibility for controlling parts of international airspace, such as those over the oceans. For instance, the United States provides ATC services over a large part of the Pacific Ocean, even though the airspace is international. Map of Sealand and the United Kingdom, with territorial water claims of 3nm and 12nm shown. ... The terms international waters, transboundary waters, or High Seas apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed regional seas and estuaries, rivers, lakes, groundwater systems (aquifers), and wetlands. ...

References

• US airspace, as described in the Aeronautical Information Manual
• UK airspace (non-authoritative source)

See also

• Airspace class