Ok, I try to learn at least one new thing a day and maybe teach a thing a day. I had seen the similarities between two of these flags before but now a third one is added into the mix today. You will never see this on western corporate media, and probably that's a good thing because they would probably use it to vilify all three entities.

So, the Imperial (and also post- Soviet Union) Russian naval flag, the CSA "Dixie" battle flag, and the most commonly used flag for "Novorossiya" all use the blue Saint Andrews cross on a red background. The Russian naval flag would have been around at the time of the formation of the CSA but I've never seen anything in my history reading that the leaders of the CSA had any dealing with Imperial Russia so I think their use of the St. Andrews cross on a red background, with the addition of the white stars on the cross representing each CSA state, came independently on its own.

The Saint Andrews cross comes from an older symbol called a "saltrie". It appears that was used by several western European areas before the Scots came used a more modern form of their St. Andrews cross flag. Why the Russian navy used a St. Andrews flag I haven't been able to track down.

https://en.wikipedia.org/wiki/Saltire

https://en.wikipedia.org/wiki/List_of_Russian_navy_flags#Jack

https://en.wikipedia.org/wiki/Flags_used_in_Russian-occupied_Ukraine

I first saw the "Novorossiya" flag without the coat of arms in the music video called the "Cuckoo" from a documentary film about the first year of the Donbass War (video came out in 2015). You can see it as a coat sleeve patch at :37-38, 3:24, and then as a flying flag from 3:37-3:44 of the video.

https://www.youtube.com/watch?v=H--ZT5vJ8_E

Anyway, I found it all interesting...

A lot more than the 3 you mentioned used this pattern also. Their all rectangular and made from cloth materials. Don't over think it.

The Saltire represents the form of cross the apostle Andrew was crucified on. So nations/cultures that venerated St Andrew often adopted the saltire.

This would include the Spanish Empire and is reflected in the state flag of Florida and Alabama. Contrary to conventional wisdom Alabama's flag is not taken from the battle flag of the confederacy just a convenient coincidence.

The use of the saltire in Southern culture goes directly back to Scotland as the largest ethnic demographic in the south were Scots of both highland and scotch-irish descent plus already being represented by the Spanish on the gulf coast.

Warrior, I'm a quarter Scot but it only went from Nova Scotia to Massachusetts until that Yankee gal met up with a German from South Dakota.

And I like Irish whiskey better than Scotch...