People from all ages like plastic model airplanes because they can be both static scale or flying models, they are affordable, and there are thousands of kits for builders.
The free flight plastic airplanes are simple and cheap, and best of all, they can fly. This kind of aircraft has no engine - it's usually thrown by hand and flies using the initial power given by your hand. Plastic is very appropriate material for them because it's light and robust and the models usually can survive many flights.
If you are buying a ready free flight plastic airplane, prepare to spend from $2-$3 to $20-$30. If you want to build one yourself, it's not much of a challenge - there are kits which can be assembled for minutes.
It's very popular to build static scale plastic airplanes from kits. Such kits can contain a lot of parts and may need to be painted or can come painted, but not assembled. Building a scale model from a kit is a lot more challenging than building a free flight plane.
Some of these kits are a bit more expensive ($20 - $100) because of the large number of details in them. The expenses can add up quite quickly, because there is a large variety of civilian and military airplanes and helicopters available as plastic kits. It's very easy to get addicted into buying more and more kits.
Finally, a large category of plastic model airplanes have a battery or gas powered engine and can fly under your remote control. The RC airplanes usually don't copy exactly real aircraft - at least not in such details like the the scale models. The RC models are very popular within the kids and teenagers because flying them is very exciting.
When you become a really advanced hobbyist, you may even build an RC aircraft yourself from scratch. Of course, you are not expected to build the engine and remote control yourself - just assembling all from a kit is challenging enough.
