Minecraft Legends

Piglin air chopper is a type a building with a large fan. You can find this kind of building in medium and large bases. If you're playing for the first time you will likely get it naturally.
I found out that choppers spawn in a quantity of 1 or 2 maximum per base. Of course they can be rebuilt after you destroy some.

Method with custom game:
1. Create Custom Game with parameters:
- Player -> Modifiers -> Player Damage - 500% in order to kill piglins faster
- Player -> Bonuses - optional, but turn everything on for safer and faster achievement
- Piglins -> Modifiers - set everything to 10% here in order to kill piglins faster
- Piglins -> Invasion Settings - increase number of medium and large bases to 2-3 for each horde
2. After you applied settings above press to save and continue.
3. Visit multiple medium or large bases to find choppers.

This achievement progress can stuck, in order to refresh it quit to main menu.