I learn't that Flying type pokemon are only the primary type in ONE pokemon. Even pidgey has 'normal' as it's primary type.

Also:
I made a list of pokemon that if I had one of each type, this would be it
Normal: Zangoose
Fire: Typhlosian
Water: Sharpedo
Grass: Venasuar
Poison: Nidoking
Fighting: Lucario
Electric: Raichu
Flying: Aerodactyl
Ice: Articoono
Psycic; Grumpig
Steel: Aggron
Ground: Sandslash
Rock: Kabutops
Bug: Ninjask
Ghost: Gengar
Dragon: Dragonite
Dark: Mightyena

You should try making your list, it's fun