Originally Posted by rkopka
Best way is to have both. Top and bottom different and red/green.
For fast planes (Funjet) I fly mostly with the top/bottom colours. The plane often is far away and the direction is normally obvious. They also have red/green but only very small.
For slower planes red/green is enough.
For aerobatic/3D I rely mostly on the red/green. Top/bottom is only an additional help.
- don't use too much white, you might have problems seeing the red/green
- don't rely on patterns, with some distance they just disappear, only colours remain
As stated before, it really depends on who is flying, the size/shape/speed of the aircraft, the colors and placement of the lighting, the darkness of the sky (moon/stars/ambient lighting), and the distance.
I do not think you have to use red or green (or any particular color) at all, but red and green show up well and they give us that distinct visual cue of opposites.
If you are wondering why alot of people use red/green on the wings, set yourself up a night flyer the way you want it. You might come to realize the reasons that so many people use colors to differentiate between left/right.