Civil aviation is one of two major categories of flying, representing all non-military and non-state aviation, both private and commercial. Most countries in the world are members of the International Civil Aviation Organization and work together to establish common Standards and Recommended Practices for civil aviation through that agency.
Civil aviation includes three major categories:
Commercial air transport, including scheduled and non-scheduled passenger and cargo flights
Aerial work, in which an aircraft is used for specialized services such as agriculture, photography, surveying, search and rescue, etc.
General aviation (GA), including all other civil flights, private or commercial
Although scheduled air transport is the larger operation in terms of passenger numbers, GA is larger in the number of flights (and flight hours, in the U.S.) In the U.S., GA carries 166 million passengers each year, more than any individual airline, though less than all the airlines combined. Since 2004, the U.S. airlines combined have carried over 600 million passengers each year, and in 2014, they carried a combined 662,819,232 passengers.
Some countries also make a regulatory distinction based on whether aircraft are flown for hire, like:
Commercial aviation includes most or all flying done for hire, particularly scheduled service on airlines; and
Private aviation includes pilots flying for their own purposes (recreation, business meetings, etc.) without receiving any kind of remuneration.
All scheduled air transport is commercial, but general aviation can be either commercial or private. Normally, the pilot, aircraft, and operator must all be authorized to perform commercial operations through separate commercial licensing, registration, and operation certificates.
Non-civil aviation is referred to as state aviation. This includes military aviation, state VIP transports, and police/customs aircraft.
Post-war aviation
After World War II, commercial aviation grew rapidly, using mostly ex-military pilots to transport people and cargo.