The earliest examples of electronically guided model airplanes were hydrogen-filled model airships of the late 19th century. They were flown as a music hall act around theater auditoriums using a basic form of spark-emitted radio signal. In 1920s, the Royal Aircraft Establishment of Britain built and tested the Larynx, a monoplane with a 100-mile (160 km) range powered by a Lynx engine. It was not until the 1930s that the British came up with the Queen Bee, a modified de Havilland Tiger Moth, and similar target aircraft.
There are many types of radio-controlled aircraft. For beginning hobbyists, there are park flyers and trainers. For more advanced pilots there are glow plug engine, electric powered and sailplane aircraft. For expert flyers, jets, pylon racers, helicopters, autogyros, 3D aircraft, and other high end competition aircraft provide adequate challenge. You can also build scale models of manned aircraft. Some models are made to look and operate like a bird instead. Other sport aircraft are designated for scale-like flying referred to as "scale". Scale is a very demanding but rewarding aspect of the hobby.
What's it worth? Take a look at this Rc Plane price guide: sold listings for a value indication.