Tracer ammunition colors per country

[Jaws2002]

It really depends on a multitude of factors. It depends on what kind of planes you run into. The only green tracer in the game is found on the Russian .30 cal. Later Russian planes didn't have them. The UB 12.7mm has white tracers, the Russian 20mm's have red and yelow tracers.
The germans in game have red for .30cal, blue for 13mm and 20mm and yellow for 30mm guns.

You can't exactly identify planes by the tracer collor but it helps once you know how the tracers look.