Question: What's A Good Size For An Indoor RC Airplane?
The best size for any RC airplane depends, in part, on where you want to fly. Larger airplanes naturally require larger spaces.
Answer: RC airplanes with a wingspan of more than 30 or so inches are generally not good candidates for indoor flight. They are simply too big to control in a confined space and their turning radius (the amount of space it takes to make a turn) is too much for a lot of indoor venues.
Small Indoor SpacesFor flying around inside your living room, garage, or office you'll probably need an RC airplane with around a 6 to 8 inch wingspan -- unless you have a really large living room. There are a few micro RC airplanes that could fly well enough in a 10'x10' space but larger rooms are better, even for the tiniest of planes.
Large Indoor SpacesIf you have access to school gyms, warehouses, or airplane hangars then you can fly indoor RC airplanes with 20 or possibly as much as 40 inch wingspans. Planes of that size can often be flown outdoors too. And of course, you can still fly the tiny RC airplanes in these large indoor spaces as well.
WeightIn addition to the wingspan, weight is also an issue. If you're flying around in your living room you want a plane that's not going to put dents in the wall or knock over table lamps. Many of the tiny indoor flyers weigh just an ounce or less.