Here’s a circular rainbow from an aircraft a skydiver:

EDIT: image embedding didn’t work

EDIT 2: not from a plane

EDIT 3: sorry for all the edits, fixed image

I’m not an expert, but I guess it would depend on the speed of sound in the rod.

It automatically replies when it can read/summarize a site, but that isn’t always possible (maybe it has problems with some paywalls).