Model aircraft are flying or non-flying models of existing or imaginary aircraft, often scaled down versions of full size planes, using materials such as balsa wood, foam and fiberglass. A vast array of designs are possible, from very simple gliders, to highly accurate scale models, some of which can be very large.Models may be built either as static non-flying models, or as flying models (also known as aeromodelling). Construction techniques for the two are usually very different.