One particular type of operating lease is the wet lease, in which the aircraft is leased together with its crew. Such leases are generally on a short-term basis to cover bursts in demand, such as the Hajj pilgrimage. Unlike a charter flight, a wet-leased aircraft operates as part of the leasing carrier's fleet and with that carrier's airline code, although it often retains the livery of its owner.
Though the early Lockheed Jetstar had four, most production business jets have two jet engines, mostly rear-mounted podded engine. If mounted below their low wing, it wouldn't allow sufficient engine clearance without a too long landing gear. The HondaJet is the exception with its over the wing engine pods. Dassault Falcon still builds three-engine models derived from the Falcon 50, and the very light jet market has seen several single-engine design concepts and the introduction of the Cirrus Vision SF50 in 2016.