Lycoming is a major American manufacturer of aircraft engines. Headquartered in Williamsport, Pennsylvania, Lycoming produces a line of horizontally opposed, air-cooled, four-, six- and eight-cylinder engines including the only FAA-certified aerobatic and helicopter piston engines on the market. The company has built more than 325,000 piston aircraft engines and powers more than half the world's general aviation fleet, both rotary and fixed wing. The company is currently part of Textron's Avco Corporation.