Pat the drumsticks very dry. Preheat the air fryer to 380°F if recommended.
Combine baking powder, paprika, garlic, onion, salt and pepper.
Rub chicken with oil, then toss with the dry seasoning until evenly coated.
Arrange in one uncrowded layer. Cook at 380°F for 12 minutes.
Turn and rotate the drumsticks; cook for 10 minutes more.
Continue for 2 to 6 minutes as needed, until the thickest pieces reach at least 165°F without touching bone.
Increase to 400°F for 2 to 4 minutes for crisper skin, then rest uncovered for 5 minutes.