There's a a great article in Collectors Weekly (I'm a sad old git) about the way American World War Two (and later) pilots and crew used to decorate their leather jackets, which have since become collectible items. As it states in the article, most of the men were still pretty young, did not expect to live long, and reverted back to the iconic images of their not so long distant youths for their designs. The commanders tolerated this as it was a way for the men to cope with the huge amounts of stress that they must have been under.
The item at the bottom is known as a blood chit, and was sewn inside of the jackets, to be used as an extra pocket, but more importantly, it has the message in Chinese that there will be a reward if the person the jacket belongs to is assisted to safety. Once again, people had it tough in the old days.