[Menarker]

I'm assuming you mean the three original legendary birds, Articuno, Zapdos and Moltres, since other legendary flying bird-like pokemons like Ho-oh and Lugia came out afterwards.

Dodrio seems funny in that it doesn't actually have wings to fly with. Its more of a jumper. :3 (And yes, it can learn Fly)

Then again, if that ever really bugged you, there are tons of other normal flying types like Staraptor, Swellow, Pidgeot, among many others. =P

And that's before considering other types like Tropicus for grass/flying (but we already have too many of those with Jumpluff and Shaymin), Honchcrow for dark/flying, several dragon/flying like Salamence and Dragonite, several bug pokemons that fly (although those tend to be low power) although Yanmega is decent enough, Xatu the psychic type, Crobat for poison. Hell, Gliscor for the paradoxical ground/flying type.

Anyhow, off to work.