I've seen several gas powered model jet airplanes at air shows. Do these smaller engines take the same type of fuel as their full-size counterparts, or do they just use 2-cycle gas like their propeller brethren?
I think the only real answer is... it depends on the model. Obviously producers can make whatever they like, though I've never actually heard of a model plane which runs on actual jet fuel (probably because it's far more difficult to get your hands on jet fuel than on the fuel you can get at any gas station).
In fact, some models even come with an electric option (Electric Duct Fan).