Private aviation is the part of civil aviation that does not include flying for hire.
In most countries, private flights are always general aviation flights, but the opposite is not true: many general aviation flights (such as banner towing, charter, crop dusting, and others) are commercial in that the pilot is hired and paid. Many private pilots fly for their own enjoyment, or to share the joys and convenience of general aviation with friends and family.
In private flight the pilot is not paid, and all aircraft operating expenses are generally paid by the pilot. In some countries such as the United States, aircraft operating expenses for a flight may optionally be divided with any passengers up to a pro rata amount. For example, if aircraft operating expenses total $120 for a flight with pilot and three passengers, each of the three passengers could pay not more than $30 (one fourth) of the expenses with the remainder paid by the pilot.
In many countries, private aviation operates to less strict standards than commercial aviation. For example, in Canada and the United States, aircraft owners are allowed to perform basic maintenance tasks (such as oil or tire changes) on their own aircraft, but only licensed mechanics may perform those tasks on aircraft used for commercial operations. Private pilots normally are not required to demonstrate the same level of proficiency on their flight tests and take fewer and less rigorous medical examinations, than are required for Commercial pilots who are paid for operating an aircraft. The majority of active pilots hold a Private Pilot license.
It is the purpose of the flight, not the aircraft or pilot, that determines whether the flight is private. For example, if a commercially licensed pilot flies a registered plane to visit a friend or attend a business meeting, most countries would consider this to be a private flight. Conversely, a private pilot could legally fly a multi-engine complex aircraft carrying numerous 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).