Half of the fleet is in the U.S. and Canada, mostly operated by firms or individuals owning a single aircraft and typically flown by their owners, with some owners defraying a portion of the fixed operating costs by sharing use with air charters. Outside of North America, most are exclusively flown by third-party crews. Most of the other half of the fleet is based in Europe : 23 aircraft in the British Isles, 20 aircraft in Austria, 20 in France, 11 in Germany, six in the Czech Republic, five in Switzerland and four in Italy.