The International Civil Aviation Organization (ICAO) defines civil aviation aircraft operations in three categories: General Aviation (GA), Aerial Work (AW) and Commercial Air Transport (CAT).
General aviation (GA) is defined by the International Civil Aviation Organization (ICAO) as all civil aviation aircraft operations with the exception of commercial air transport or aerial work, which is defined as specialized aviation services for other purposes.However, for statistical purposes ICAO uses a definition of general aviation which includes aerial work. General aviation thus represents the “private transport” and recreational components of aviation.
General Aviation includes commercial activities such as corporate and business aviation, as well as non-commercial activities such as recreational flying. Most commercial aviation activities require at minimum a commercial pilot licence (CPL), and some require an airline transport pilot licence (ATPL). In the United States the pilot in command of a scheduled air carriers’ aircraft must hold an ATPL
Aerial work operations are separated from general aviation by ICAO by this definition. Aerial work is when an aircraft is used for specialized services such as agriculture, construction, photography, surveying, observation and patrol, search and rescue, and aerial advertisement.
Commercial aviation is not a rigorously defined category. All Commercial Air Transport and Aerial Work operations are regarded as commercial aviation, as well as some General Aviation flights.
Commercial Air Transport is defined as an aircraft operation involving the transport of passengers, cargo or mail for remuneration or hire. It includes scheduled and non-scheduled air transport operations. Aerial Work is defined as an aircraft operation in which an aircraft is used for specialized services such as agriculture, construction, photography, surveying, observation and patrol, search and rescue, advertisement, etc.
Air charter is the business of renting an entire aircraft (i.e., chartering) as opposed to individual aircraft seats (i.e., purchasing a ticket through a traditional airline).
Charter – also called air taxi or ad hoc – flights require certification from the associated country’s civil aviation authority. The regulations are differentiated from typical commercial/passenger service by offering a non-scheduled service. Analogous regulations generally also apply to air ambulance and cargo operators, which are often also ad hoc for-hire services.
It is the purpose of the flight, not the aircraft or pilot, that determines whether the flight is commercial or private For example, if a commercially licensed pilot flies a plane to visit a friend or attend a business meeting, this would be a private flight. Conversely, a private pilot could legally fly a multi-engine complex aircraft carrying passengers for non-commercial purposes (no compensation paid to the pilot, and a pro rata or larger portion of the aircraft operating expenses paid by the pilot).