RE: quesiton about my new nexstar
The reason is the plane does not operate in the same dusty environment that most nitro cars and trucks do. There is no dust/dirt in the air, and since the majority of runways are grass or asphalt there is no dust/dirt there either. If you plan on operating your plane off of a pure dirt runway you might want to think about an air filter, but you could probably do without it there too. It's really as simple as planes and cars operate in two totally different environments.
Hope this helps
Ken