These are the smallest of the small. Tiny micro RC airplanes that can fly almost anywhere indoors. They may be tiny but they aren't necessarily designed for tiny fingers -- because of their delicate nature and cost. These are presented below roughly in order from Smallest to Largest (of the small).
Micro Butterfly
This Plantraco airplane has a super small 3.5" wingspan. The tiny 2-channel receiver provides throttle and rudder control. You can purchase it with or without a transmitter. Despite its size, Plantraco says it can even handle a little wind.Carbon Butterfly
Carbon Butterfly Image Courtesy of PriceGrabber
Weighing in at just 3 grams (that's about 0.1058 ounces), this is the carbon fiber version of Plantraco's Butterfly Livingroom Flyer. It comes in an aluminum briefcase along with the FMS flight simulator. This is no cheap toy. There is also a "just the plane" version where you supply your own transmitter.
