
Almost all production business jets, such as General Dynamics' Gulfstream and the Gates Lear Jet (now built by Bombardier), have had two or three engines, though the Jetstar, an early business jet, had four. Advances in engine reliability and power have rendered four-engine designs obsolete, and only Dassault Aviation still builds three-engine models (in the Falcon line). The emerging market for so-called "very light jets" and "personal jets", has seen the introduction (at least on paper) of several single-engine designs as well.
Almost all business jets have rear-mounted engines, because the wing (mounted low for performance reasons) is too near the ground for engines to be slung underneath it.
Airliners are sometimes converted into luxury business jets. Such converted aircraft are often used by celebrities with a large entourage or press corps, or by sports teams, but airliners often face operational restrictions based on runway length or local noise restrictions.
A focus of development is at the low end of the market with small models, many far cheaper than existing business jets. Many of these fall into the very light jet (VLJ) category and are used by the air taxi industry. Cessna has developed the Mustang, a six-place twinjet (2 crew + 4 passengers) available for $2.55 million USD. A number of smaller manufacturers have planned even cheaper jets; the first was the Eclipse 500 from the now defunct Eclipse Aviation which was available at around 1.5 million USD. It remains to be seen whether the new jet manufacturers will complete their designs, or find the market required to sell their jets at the low prices planned.
There are approximately 11,000 business jets in the worldwide fleet with the vast majority of them based in the United States or owned by US companies. The European market is the next largest, with growing activity in the Middle East, Asia, and Central America.
Since 1996 the term "fractional jet" has been used in connection with business aircraft owned by a consortium of companies. Costly overheads such as flight crew, hangarage and maintenance can be shared through such arrangements.
Because of their low-volume productions and long lead times, new aircraft orders can take two to three years for delivery. This peculiarity fuels a large pre-owned marketplace, with aircraft for immediate availability.
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