Ground
Ground and Flying types: weaknesses, resistances and Pokémon
Ground and Flying Pokémon take quadruple damage from Ice moves, take double damage from Water moves, resist Fighting, Poison and Bug moves and are immune to Electric and Ground moves.
The balance is even: 2 weaknesses and 5 resistances or immunities.
Ground moves are super effective against Fire, Electric, Poison, Rock and Steel and not very effective against Grass and Bug. Flying moves are super effective against Grass, Fighting and Bug and not very effective against Electric, Rock and Steel.
To beat these Pokémon, your best pick is Ice moves. Avoid Fighting, Poison, Bug and Electric moves, which deal little or no damage.
There are 3 Pokémon with this combination, such as Gligar, Gliscor and Landorus.