Altaria and Swablu are only part cloud, thats why, he means pure clouds, y'know those fluffy things in the sky without bird bodies?
and Kangaskhan is a kangaroo, surprised you never noticed, it looks just like a kangaroo except its a cartoon, and its bigger and it doesnt jump like a Kangaroo.

I've known that kangaskhan was a kangaroo ever since i first saw one

yeah, i know wth a cloud is. But tell me: how interested do you think an eight-year old would be in a cloud with a smilie face?? although i suggested something similar earlier, i rather doubt that it'll happen. and i won't bother discussing kangaskhan because it would be off-topic.

it would not be a cloud with a smiley face

Then the answer is simple. Make a Pokémon that can fly, is very different from life that naturally occurs on Earth, and remove all elemental powers.

like a little fluffy ball of fuzz that can fly?

No! Koromori is half psychic
But it doesnt have to be a simple cloud if it will be a cloud at all.

I at least hope if this family ends up existing (doubtful) that the youngest evolution is a cloud with a smiley face.
A la Mario or Yoshi Story.

I don't think a cloud would be able to 'roost'.

its simple, the cloud just falls to Earth, of course then it would be fog, oh maybe if it uses roost it creates a fog but the cloud pokemon wouldnt lose accuracy.

heh, i dont know, but truth be told, the only way you could kill a cloud/fog is with defog, unless it wass a solid cloud

why does it need that move..?? unless i'm mistaken, i'm pretty sure there are flying-types that don't have that move...

that's a good point actually...

Not every flying type needs Roost. Plus, if resembling a real animal qualifies a Pokémon as "normal", then a flying Eeveelution would be possible , too. The only reason that one does not exist is that all of our non-elemental flyers are birds or dragons.

not to ruin your ideas... but literally speaking, isn't a cloud a bunch of water vapor. and when it comes close to earth, it does become fog. and doesn't fire make fog go away? so wouldn't a cloud be weak against fire, even though flying is weak against fire? hmm, and wasn't castform a cloud? he wasn't pure flying, but they had the whole point that hes a cloud pretty spot on. maybe thats just my opinion. anyways, go on.

Actually, Castform is based on teru-sama, a traditional japanese model to bring good weather. Also, going with the cloud idea, what about a twister or mushroom cloud (although maybe a bit insensitive to the japanese and others in general)

twister pokemon could be a good candidate. mushroom cloud would probably be fire type, just saying...

twister is a dragon move and mushroom will make game freak make it grass or bug flying(sorry, but it is true)
i think that game freak hate pure flying pokemon like they hate bug pokemon.
but we ould hav this...
fa' fetched evo
cra' fetched
flying type
description:
when fa' fetched evolved, its wings became tolarge for it to stay on the ground(or it might not be able to get back up), so it took to the skies and hasn't come down since. it is only rarely seen because of this. on the back of its wings, the stick it holds has fused with it and is its energy supply. it hunts smaller birds and is know as the king of the sky. its back legs hav become large wings like the front(like a crobat).
acctully, don't try this at home kids. DANGEROUS!

There all ready is a pure flying type Arceus with a sky plate

We already know about Kecleon, Arceus, Ditto and Mew (which can transform into Arceus), the Porygon family, and Smeargle (which can sketch Transform, and then transform into your opponent's Arceus). We're talking about Pokémon which are listed in the National Pokédex as a pure Flying-type, and do not have another more accessible form.

Twister cloud Pokémon = Hail Castform

Twister Pokemon = Not done before.
Castform is weather related, duh. We've covered it fifty times in this thread.

What we Don't have yet is a Pokemon specifically designed to be a cloud, and nothing else.
Nor do we have a Pokemon specifically designed to be a twister/tornado, and nothing else.

Also, I see how Twister is a Dragon-typed move, but that doesn't necessarily mean it would be a Dragon-typed Poke.
(I assume that's what you were trying to say.)
SUPER loose example, because I'm too tired to think of a good one:
Tail Glow is a Bug-typed move, yet the Pokemon whose entire being revolves around its tail glowing is Electric-typed.

I KNOW there's a better example to go along with what I'm trying to say...sorry I can't recall it.
Bottom line: I think a Twister-based Poke would be Flying-type, but probably still learn Twister. And Fire Spin. And Razor Wind. And Rain Dance. And Hail. And Icy Wind. And Leaf Storm. And Stone Edge. And Tail Wind. And Silver Wind. And Thunder/bolt/Discharge. And Vacuum Wave. And Whirlwind. And Fire Spin. And Rapid Spin.

Oh my God I want this to exist.