I just bought this game so perhaps I missed it, but it doesn't seem there's a way to sort ships other than alphabetically? I went perhaps a bit overboard in designing ships and way wondering if there was a way than I could assign categories to ships - "Missile Ships", "Gun Ships", "Laser Ships", "Transports", and so on, so when I wanted to choose a particular design I'd have fewer to scroll through after choosing a category. I ended up creating a spreadsheet of all my designs, which worked, but in-game would have been better.

Thanks goodness I found the "obsolete" button - otherwise it would have been even worse!