A helicopter is an aircraft that is lifted and propelled by one or more horizontal rotors. Helicopters are powered either by a piston engine that uses 100-octane low-leaded fuel or a turbo-shaft engine that uses Jet A fuel. Turbo-shaft engines are a form of gas-turbine propulsion designed to produce shaft power rather than jet thrust. They are typically used for very short business aviation flights of less than 100 miles, at altitudes of less than 1,000 feet. The interior of a business helicopter typically seats 4-6 people and is configured similar to the inside of a small car. Helicopters are often attractive to businesspeople because of their ability to land at a variety of heliports and outlying airports.