Ghost
Flying and Ghost types: weaknesses, resistances and Pokémon
Flying and Ghost Pokémon take double damage from Electric, Ice, Rock, Ghost and Dark moves, resist Bug, Grass and Poison moves and are immune to Normal, Fighting and Ground moves.
The balance is even: 5 weaknesses and 6 resistances or immunities.
Flying moves are super effective against Grass, Fighting and Bug and not very effective against Electric, Rock and Steel. Ghost moves are super effective against Psychic and Ghost and not very effective against Dark.
To beat these Pokémon, your best pick is Electric, Ice and Rock moves. Avoid Bug, Grass, Poison and Normal moves, which deal little or no damage.
There are 2 Pokémon with this combination, such as Drifloon and Drifblim.