Super Effective:
* Steel: Steel-type Pokemon resist both Dragon and Fairy, making them very effective.
* Poison: Poison-type Pokemon are super effective against Fairy-type Pokemon.
* Dragon: Dragon-type Pokemon are super effective against Dragon-type Pokemon (but not Fairy).
* Dark: Dark-type Pokemon are super effective against Fairy-type Pokemon.
Other Considerations:
* Ice: While not super effective against Altaria, Ice-type moves can be quite strong against it.
* Electric: If Altaria is using moves like Dragon Pulse, an Electric-type move can be very helpful.
Specific Pokemon:
* Excadrill: Steel and Ground typing, makes it very effective against Altaria.
* Scizor: Steel and Bug typing, strong against Altaria.
* Garchomp: Dragon and Ground typing, strong against Altaria.
* Metagross: Steel and Psychic typing, can be a good counter.
* Gardevoir: Psychic and Fairy typing, may be effective if you can avoid its Dragon Pulse.
Remember:
* The effectiveness of a Pokemon depends not only on type but also on its moveset, stats, and abilities.
* Consider the specific moves Altaria is using to determine the best counter.
Let me know if you want more details about a specific Pokemon!