Operating leases are generally short-term (less than 10 years in duration), making them attractive when aircraft are needed for a start-up venture, or for the tentative expansion of an established carrier. The short duration of an operating lease also protects against aircraft obsolescence, an important consideration in many countries due to changing noise and environmental laws. In some countries where airlines may be deemed less creditworthy (e.g. the former Soviet Union), operating leases may be the only way for an airline to acquire aircraft. Moreover, it provides the flexibility to the airlines so that they can manage fleet size and composition as closely as possible, expanding and contracting to match demand.
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.