Ryanair Ltd. is an Irish low-cost airline headquartered in Swords, Dublin, Ireland, with its primary operational bases at Dublin and London Stansted Airports. In 2013, Ryanair was both the largest European airline by scheduled passengers carried, and the busiest international airline by passenger numbers. Ryanair operates over 350 Boeing 737-800 aircraft, with a single 737-700 used as a backup plane and for pilot training. The airline has been characterised by its rapid expansion, a result of the deregulation of the aviation industry in Europe in 1997 and the success of its low-cost business model. Ryanair's route network serves 32 countries in Europe, Africa (Morocco), and the Middle East (Israel).