As an Army kid in Germany in the late 1960 or early 70's Cox use to make a gas powered airplane or at least the engine and the pint cans of fuel which had to be squirted in to engine to start it. I do not recall if Cox manufactured the entire aircraft I want to say they did. The engine was started using a finger to turn the prop. If you weren't careful the prop would do a number on your finger.
The model plane was operated by its handler some 25' away with three strings which came together on a end cap. If memory serves me one string operated the rudder and the other two the wing flaps.
As a 10 -12 year old, it was best three minutes I've ever got dizzy turning in circles. I remember flying a P-38 model. Does any know if these are still available or have they been replaced by RC aircraft. I believe Cox got into the RC business in later years.