As a new player, I would like to say that this was extremely useful, not just for organising carriers (I'm only quite early in my 1st game, so I don't actually have any carriers, just a couple of PDCs with hangars), but also for learning how to use the organisation window in general. It seems extremely complex, and I'm having a bit of trouble working it out, but I've done some experimenting with test branches to work out basics like moving branches around etc, and I can see how it would be extremely useful, especially when I finally start getting a decent fleet that has more than half a dozen ships. Your explanations were really succinct and to-the-point, and I think that, combined with the other bits and pieces I can find, It will be really helpful.
As a side note, I don't suppose you'd be willing to do this kind of step-by-step tutorial for the org window in general, rather than carriers specifically? The way you explain things makes it easy to work out what's going on, and labelled pics work in a way that nothing else can XD