Ready to Fly is a term used to describe radio controlled airplanes or radio-controlled helicopter

Radio-controlled helicopter

Radio-controlled helicopters are model aircraft which are distinct from RC airplanes because of the differences in construction, aerodynamics, and flight training...

s that are supplied fully built with no assembly required.

So-called "toy R/C" airplanes of the type distributed by companies like Air Hogs

Air Hogs

Air Hogs is a line of toy airplanes, helicopters, rockets, manufactured by the Spin Master company in Toronto, Canada. They are radio controlled, free-flying, and air-powered aircraft...

almost always fall under the category. However, there are models available for varying skill levels. Advanced helicopters under this category are test flown at the factory and are claimed to be able to fly "out of the box."