A model aircraft is a physical model of an existing or imagined aircraft, and is built typically for display, research, or amusement. Model aircraft are divided into two basic groups: flying and non-flying. Non-flying models are also termed static, display, or shelf models.

Aircraft manufacturers and researchers make wind tunnel models for testing aerodynamic properties, for basic research, or for the development of new designs. Sometimes only part of the aircraft is modelled.

Static models range from mass-produced toys in white metal or plastic to highly accurate and detailed models produced for museum display and requiring thousands of hours of work. Many are available in kits, typically made of injection-molded polystyrene or resin.

Flying models range from simple toy gliders made of sheets of paper, balsa, card stock or foam polystyrene to powered scale models built up from balsa, bamboo sticks, plastic, (including both molded or sheet polystyrene, and styrofoam), metal, synthetic resin, either alone or with carbon fiber or fiberglass, and skinned with either tissue paper, mylar and other materials. Some can be large, especially when used to research the flight properties of a proposed full scale aircraft.

Model aircraft are made for wind tunnel and free-flight research tests and often contain components that can be swapped to compare various fittings and configurations, or have features such as controls that can be repositioned to reflect various in flight configurations. They are also often fitted with sensors for spot measurements and are usually mounted on a structure that ensures the correct alignment with the airflow, and which provides additional measurements. For wind tunnel research, it is sometimes necessary only to make part of the proposed aircraft.

Full-scale static engineering models are also constructed for production development, often made of different materials from the proposed design. Again, often only part of the aircraft is modeled.

Static model aircraft cannot fly, and are used for display, education and are used in wind tunnels to collect data for the design of full scale aircraft. They may be built using any suitable material, which often includes plastic, wood, metal, paper and fiberglass and may be built to a specific scale, so that the size of the original may be compared to that of other aircraft. Models may come finished, or may require painting or assembly, with glue, screws, or by clipping together, or both.

Many of the world's airlines allow their aircraft to be modelled for publicity. Airlines used to order large scale models of their aircraft to supply them to travel agencies as a promotional item. Desktop model airplanes may be given to airport, airline and government officials to promote an airline or celebrate a new route or an achievement.