Cost :
Used fixed-wings can cost from as little as a couple of thousand pounds for the early machines, to as much as the mid-twenty thousand pounds for the latest high-performance machines. Most flex-wings are two-seaters, but there are a few single-seat designs available too. Engines are either two-stroke or four-stroke: the two-strokes cost less to buy but use more fuel and oil per hour, while four- strokes are more expensive initially but are more economical to run and service.