Airspace

Airspace is a portion of the atmosphere controlled by a country above its territory and territorial waters, which is under the country's sovereignty and regulatory control. Internationally, allocation and management of airspace is coordinated by the International Civil Aviation Organization (ICAO), which was established through the 1944 Chicago Convention and came into being in 1947 to unify air traffic. ICAO organizes airspace into Flight Information Regions (FIRs) and provides classification guidelines. National authorities, such as the FAA, CAA, or EASA implement rules and regulations for air traffic control, special-use airspace, and enforcement within their own FIRs. Airspace can be used for both civilian flight and for defence or military operations, and countries are responsible for protecting their own airspace using measures such as air policing. Legal and technical challenges include the vertical boundary between airspace and outer space and temporary restrictions such as NOTAMs or TFRs.