We've had a lot of ideas for Aer creature types. Have we gone far enough to ask if there's any we want to focus on?

I think my favourites are Viashino and Vedalken, but I'm not sure if those actually make sense, or if I just like them.

I feel like having 2-3 races would be right, but maybe 1 or more would be better?

Are they all winged humanoids (or do some ride griffins, etc instead?)

Is there any place for angels, demons, etc? I'm assuming we should stick to normal humanoid creatures, but I'm not sure.

Are there humans? I like the idea of excluding humans, but does everyone agree?

I have no idea where it's written, but we have discussed this somewhere before. Part of the concept of Aer is to use all of the "normal" creature types for each race so that, even though it's gold, it seems "normal" in comparison to the Gloaming. That means we should probably use the characteristic races for the majority of the colors: White is Humans, Blue is Merfolk, Black is Vampires and sometimes Zombies, Red is Goblins, and Green is Elves.
Personally, I'm not a fan of Zombies and Vampires in my Aer, but I could be persuaded to be okay with Vampries.
Aeran Elves have wings. Winged elves are common enough that I think we can pull that off fine, and Magic plays with the design of its Elves enough (Lorwyn!) that it's probably fine.
Aeran Viashino also have wings. Perhaps the merfolk do as well, if we include them (they're a bit weird to think of in a sky city, but hey, weirder things happen.)
The races that can't fly use golden Flight Halos to get around, which would be represented in the art.

As for races I think belong in Aer:

• Humans: Without them, people lose connection to the story. I think I recall Maro talking about how humans being absent from Lorwyn was unpopular. To play up the "alien" nature of the Gloaming, we need something familiar for people to connect to.
• Merfolk: An odd fit for a floating city, but they're in almost every Magic set. They might belong better in the blue play, in some twisted fashion, though.
• Vedalken: An easier fit than Merfolk, for sure.
• Viashino: Already discussed and pretty much a shoe-in. They make great sense with wings.
• Goblins: The primary red race, I feel like we'd have a hard time pulling off "normal" and "cosmopolitan" without them.
• Elves: Flying elves sounds good to me. They also lend themselves nicely to multicolor, IMO.
• Faeries: They fly, and they make so much sense in green that I'd like to put them in a set where a non-blue Faerie gets to have flying.
• Sphinxes: Honestly, the only Iconic creature that really fits the Aer flavor for me, though I could be persuaded to change my mind about Angels, Demons, and Dragons.

Pretty much any creature type you see me putting on a card is something I think would be a good fit for Aer.

I don't think you need Goblins to sell a set. In my mind, it would make more sense if the residents of Aer could all get along in some fashion or another, within tight quarters... and goblins don't really fit that role as well as Viashino do (or possibly dwarves?)

Flying merfolk are fine by me... but it does presume that there's a body of water somewhere for the mer to dip in. Maybe that just encourages odd architecture? I don't know. But you'd think Aven would just make more sense. Especially since they're the go to White/Blue tribe.

Ah yes, I didn't even mention Aven. I kind of took them as a given, I suppose.

there's harpy and their new cousins, siren

Harpies already exist in the Gloaming. Siren is a creature type I've thought about, but I'm not sure if it makes sense for Aer or not. I suppose they'd have a fun time singing at the Aeran opera. The only Siren previous to Theros, Alluring Siren, didn't fly, by the way. Weren't the Sirens in the myth not creatures that flew, either?

Nope. Sirens were half-bird in the Odyssey. But Harpies were also half-bird. I get the impression that 1970s Monster Manuals for Dungeons and Dragons had something to do with the now fishy nature of Sirens. TSR probably needed to make the two monsters distinct from each other. Harpies were bird ladies, but Sirens were creatures that drew you to a drowning death by singing to you... they didn't need to be bird ladies, so they stopped overlapping.