Combine the egg, Parmesan cheese, milk, breadcrumbs and garlic powder in a large bowl. The meatball mixture should have a thick consistency.
Stir in the ground turkey and mix well to combine.
Coat your hands in a little olive oil. Form 12 meatballs using your hands. (For uniformly sized meatballs, try using a large cookie scoop or small ice cream scoop). Place the meatballs on a nonstick baking sheet or sheet of parchment paper.
Preheat oven to 400F degrees. Coat the air fryer basket with nonstick cooking spray. Place the meatballs into the basket in a single layer.
Air fry for 4-5 minutes. Flip. Air fry for an additional 4-5 minutes, until meatballs are golden brown.