On rare occasions paint jobs were done with the intent of making the aircraft easier to see. In World War II fighter and bomber aircraft took off from separate bases in North Africa. For missions to bomb targets in Europe, the two groups would rendezvous over the Mediterranean and here is where the trouble began.   The gunners on the bombers would be inexperienced in aircraft recognition or nervous wrecks or both.   They could see specks approaching the bomber formation, assume the specks to be enemy fighter aircraft with the results being a friendly fire incident.   Therefore the escort fighters had to approach on a parallel course, a nonthreatening course and slowly converge with the bombers to allow the specks to become recognizable profiles.  The most important word in the last sentence is "slowly."  Because of this pattern of merging the two groups, the tail of the aircraft became the perfect place to paint a "signal" to the gunners that the fighter aircraft were "friendly."   Painting the tail red proved to be that signal.   There are many books about the Red Tails.   Here is one place to start: Freedom flyers : the Tuskegee Airmen of World War II by Moye.