Do they just automatically load older stuff in the same series of missiles if you don't have newer ones on hand?
That happens to me yes. I presume that happens all the time... ?
Yep. Isn't it nifty?
It used to be a total pain to load ammo, since if enough of the right kind of missile wasn't available, it would just leave the ship empty (or actually take missiles off, if they weren't in the default loadout). That's what series were introduced for - essentially your loadout is saying "I want 200 Sidewinder, 100 Sparrow, and 20 Harpoon" - Aurora fills it with the most recent missiles (assuming you've updated loadout when you design your new missiles).
There's still a request in to be able to define multiple loadouts for a single class (e.g. mission-based loadouts), but you can't have everything
John