Firstly, I apologise for the nature of the question; I don't wish to upset anybody, it's just something that interests me.
During WWII, a number of German companies received financial backing and slave labourers from Hitler. Companies such as Hugo Boss, Volkswagen and Lufthansa.
A thread on Airliners.net from 1999 mentions a documentary showing Lufthansa planes flying with the Swastika on their tail. I found this image online:
What is the story behind Lufthansa's involvement with the Nazis?
How were they allowed to continue flying after WWII?