The game allows you to assign tactical codes.  Each aircraft/nation has a specific number of symbols allocated to specific positions.  The following is a combination of quick reference for what the game does and how it corresponds to historical markings.

 

Colors for German:
Black, White, Yellow, Red, Green, Blue

 

Colors for German:
Black, White, Yellow, Red, Blue

 

Colors for Britain:
White, Blue, Red, Sky

 

Colors for USA:
Black, White, Yellow, Red, Blue

=========================================

Russian:
2 Numbers on the fuselage
5 Possible number styles
Russian colors

 

Russian numbers from 1-10 come in 5 different styles.

"%21", "%22","%23", "%24", "%25", "%26", "%27", "%28", "%29", "%2a"
"0", "1","2", "3", "4", "5", "6", "7", "8", "9"
"%3a", "%3b","%3c", "%3d", "%3e", "%3f", "%40", "A", "B", "C"
"D", "E","F", "G", "H", "I", "J", "K", "L", "M"
"N", "O","P", "Q", "R", "S", "T", "U", "V", "W"
 

Exceptions:
Lagg3 (have not yet looked at every plane)
4 Numbers.  First two are fuselage and second two are tail.  

 

Britain:
3 Numbers/Letters
1 style
Usually Sky.  I think some white on bombers and sometimes blue early war.

Seems to be consistent for all planes


USA general:
3 Numbers/Letters
1 style
Usually white if the skin is green or black if the skin is silver.
While Red. Yellow, and Blue are options I have seen no evidence of their use except as outlines on black/white markings

German:
let the fun begin
Bombers: 4 possible numbers/letters.
Letters 1 and 2:Geschwader Identifier
Cross +
letter 3: Aircraft Id (red or otheer color)
Letter 4: Staffel Id

Fighter:
Symbol 1 and 2: Number: Aircraft Id.  Can be Geschwader markings instead of a number
Cross +
Symbol 3: Gruppe Id.  Blank for I, - or ~ for II, | for 3, + or cocked ~ for IV
- = %3b
~ = %3e
Cocked ~ = %3d

<<  = Geschwader Commodore
<|  = Geschwader Adjudant
<-  = Geschwader IA
<O| = Geschwader Technical Officer
<|| = Geschwader Stab

