I always had an interest in planes ever since I was a kid.  But there has always been something that I couldn't really understand, and that is with the old era planes such as World War II era. The plane always seems to have some kind of pictures or writings on it, but has nothing to do with the military or being patriotic.  But rather, to put it harshly "unprofessional" and in a way would have been forbidden in today's military aviation.  Take for example the above photos, at the front of the air-craft there is a picture of a girl that looks as if she's a prostitute or a male "sex" symbol.  There are more of this kind of photos in older planes just like this.  At first I wondered why the AirForce even allow it to be posted on, later I realized it is something like a personalization of the plane by its crew.  A way of boosting morale because during World War II, these are the bombers of the war.  It would fly deep into enemy's territory to deliver its payload, and a lot of these bombers would never make it back and so although the pictures is "unprofessional", it does its job at promoting morale.

-Thinh