When a plane can swap top and bottom very rapidly, it is important to know what side you're seeing...
A ZAGI type for instance....
For medium to distant flying, with manuvering involved, top-bottom becomes very important, as well
as orientation. These planes show why a light colored top and dark colored bottom are most effective:
The white stripes on the bottom of this Sometthin' Extra really enhance manuvering at a distance..
SIG Fazer with CAP type tail end, very easy to fly
Semi-scale with stripes is VERY visible
.
Orange (dark) white (light)
.
Yellow with big blue patches on the bottom... easy to see