[DabbyDabberson]

My assumption is that foo fighters are a different but related phenomena.

Foo fighters were likely not weather, but a product of the aircraft themselves.

The most likely theory I've seen for foo fighters, is that the massive propellers on WWII era aircraft , spinning at high altitude in super dry air, collected a ton of static electricity, which caused a phenomena similar to ball lightning.

[tomcam]

Quite possibly right. Hard to reproduce in either case.