Fractional ownership of aircraft involves an individual or corporation who pays an upfront equity share for the cost of an aircraft. If four parties are involved, a partner would pay one-fourth of the aircraft price (a "quarter share"). That partner is now an equity owner in that aircraft and can sell the equity position if necessary. This also entitles the new owner to a certain number of hours of flight time on that aircraft, or any comparable aircraft in the fleet. Additional fees include monthly management fees and incidentals such as catering and ground transportation. In the United States, fractional-ownership operations may be regulated by either FAA part 91 or part 135.
The forward wing sweep, 20,280 pounds (9.20 t) MOTW Hamburger Flugzeugbau HFB 320 Hansa Jet first flew on 21 April 1964, powered by two General Electric CJ610, 47 were built between 1965 and 1973. The joint Piaggo-Douglas, 18,000 pounds (8.2 t) MOTW Piaggio PD.808 first flew on 29 August 1964, powered by two Armstrong Siddeley Vipers, 24 were built for the Italian Air Force.