Will you tell me where to get these aerial enemies?
Where is this mod?

"Yes, this turret will ONLY target entities with the trigger_target_mask 'air-unit'. That means the player or entities that are able to be targeted and got the mask assigned to by other mods."

Meaning in vanilla there's only the player who gets targeted. Unless some other mod assigns the trigger_target_mask air-unit to another entity, it's only that. This mod primarily exists for the use against my planes, that per default are immune to the vanilla damage types.