
Not so long ago, mini rc airplanes would have been "made to measure" by indoor flying enthusiasts using normal free flight indoor model plane kits and modifying them to take the new breed of micro servos, receivers, battery packs and motors.
This, of course, made them rather expensive and a fair knowledge of model airplane building was needed to carry out the necessary modifications.
But now RTF (Ready To Fly) mini rc airplanes are commonplace, and will become even more so as radio control technology continues to advance.
A shining example is Parkzone's Cessna 210, a fully proportional 3 channel electric airplane supplied with the latest 2.4GHZ digital radio system! The ultimate in RTF small-scale models, the Cessna even comes with a display stand so can double up as a static piece in your living room.

Above, Parkzone's Cessna 210 is an excellent example of a fully functional mini rc airplane
Of course, there's no official size that defines "mini", but any plane with a wingspan of under, say, 20 inches can safely be put into the mini category.
The availability of such rc planes is getting better all the time, and such models can even be bought from toy shops around the world - they're not restricted to specialist model shops any more.
Another great example, again from Parkzone, is the new Ember, shown below...

Like the Cessna, the Ember also comes with 2.4GHz radio as standard, and its slow flying capabilities and small 16 inch wingspan make it an ideal candidate for some gentle indoor flying.
Two less expensive examples of these mass-produced RTF mini planes are Megatech's X-EC Diversion and Firefly, both shown below:

At 21" long and with a wingspan of just 14", these models (essentially the same airplane in different guises) feature the very latest 'space-age' micro-processor technology and are powered by twin micro motors which are used to control direction and altitude from a single stick rc transmitter.
These simple mini rc airplanes can easily be flown by beginners and are practically ready to fly straight out the box; only batteries for the radio gear are needed separately.
Such models are perfectly suited to indoor flying in larger areas such as a school sports hall, and are fantastic little models to fly around a decent sized backyard, or of course a parking lot or park.
Outdoor flying is restricted to wind-free days though, as these mini airplanes have little weight to them so it doesn't take much of a breeze to adversely effect the model in flight.

I'm personally a great fan of small rc models, and the X-EC and Firefly mini rc airplanes are great value both in terms of cost but more importantly in terms of great fun. The Cessna 210 is a step up, and is already proving to be a massive success.
Watch the flight video (X-EC).
Of course, as radio control technology continues through it's seemingly unstoppable revolution, mini rc airplanes are going to get even more complex than the 3 channel Cessna 210 shown at the top of the page.
I'm sure that it won't be long before we can buy a 10" wingspan, multi-channel fully RTF scale warbird, complete with retracts!
And smaller rc models will always have a huge fanbase - myself included!
The X-EC Diversion and Firefly mini rc airplanes are both available from RC Discounts, and the Parkzone Cessna 210 from Red Rocket Hobby Shop.
Micro rc airplanes - the really small stuff!
Indoor rc airplanes - a rapidly growing sector of the hobby.