Ever wonder where the Foo Fighters got their name?

I was just reading a book about nazi secret weapons. There was a phenomena, mostly seen in W Europe, by allied airmen. Strange lights or globes/disks etc would show up and follow the planes. They never acted in an aggressive manner though sometimes their appearance would mess up radar or other instruments. The airman came to refer to these as foo fighters. How that name arose is not known for sure, but there are a couple theories. The lights quit appearing once the allies had crossed the Rhine which supported the idea that they were some Nazi tech.