Simple Plastic Airplane Design (SPAD) is term used to describe a type of radio controlled airplane.
The airplane is usually, though not always, simply built with the body consisting of a lightweight plastic material such as gutter downspout or an aluminium rail. The wings are made of an equally light material such as foam or coroplast. The remaining components added to the plane are virtually the same as you would find in any other RC plane of similar size.
This concept of building simple radio controlled airplanes using cheap materials without the time consuming and painstaking process of working with balsa wood and iron-on plastic coating was popularized by a web site created in the late 90's which sparked much interest in this field, www.spadtothebone.com. While this web site, and the many original plans and articles still exist, the main gathering place for Spad enthusiasts on the web today resides at www.spadworld.net.
SPADs are a cheaper and simpler alternative to the popular balsa RC planes for a variety of situations. Some of these include: RC Airplane Combat, 3D Flying, and in places where you would normally not risk a more expensive plane.
Source: Wikipedia (All text is available under the terms of the GNU Free Documentation License)
For More Information: Airplane Wing Types, Design, Science & Experiments