Add the frozen meatballs to the air fryer basket in a single layer, without crowding. Spray lightly with olive oil.
Set the air fryer to 380 degrees F and cook for 8–10 minutes, shaking the basket halfway through. Meatballs are done at 165 degrees F internally.
Meanwhile, in a small saucepan over medium heat, add the butter and minced garlic. Sauté 2 minutes, until the garlic is soft and fragrant. Do not let it brown.
Add the ketchup, honey, and soy sauce. Simmer, stirring, for 3–4 minutes until the sauce comes together and thickens slightly.
Optional: For a thicker, stickier glaze, stir in the cornstarch slurry and simmer 1 minute more.
Remove the sauce from the heat. Add the hot meatballs to a large bowl, pour the sauce over, and toss to coat. Serve immediately.