I know what you mean about electric RC cars, dead easy to start and clean (you can use them in the house).
I used to do loads of IC car and buggy stuff but it was messy and frustrating if they wouldnt start. After a few years I wanted the extra dimension so started flying IC planes but since having babies I have not had the time - can't wait till they are older.
Here is one of my "modified planes" - do a search on youtube for "rocket firing plane"
