Electric, ice and rock attacks are super effective (2x) against the flying type. Not very effective (0.5x) are bug, fight and grass attacks and ground attacks do no damage at all against flying type pokémon.
Since generation 2, flying pokémon aren't affected by attacks that only affect pokémon on the ground (such as earthquake).
There are 22 flying-type Pokemon.
Swanna is a Water and Flying type pokemon.
Jumpluff is a Grass and Flying type pokemon.
Electric Pokemon are weak to Ground and Ice moves
Flying type Pokemon are good against normal Pokemon.
Crobat is a Poison and Flying type pokemon.
The weakness of flying type Pokemon is Ice, Electric and Rock.
Find a Flying-type Pokemon and catch it. There are plenty of them in each game and many Flying-type Pokemon are common Pokemon, so you shouldn't have trouble doing so.
Thundurus is an Electric and Flying type pokemon.
Altiria is a flying type pokemon.
Tornadus is a Flying type pokemon.
The Pokemon taillow is a Flying Type