Preheat the air fryer: Set to 380°F (193°C) for 3–5 minutes so it’s hot when the meatballs go in.
Hydrate the breadcrumbs: In a bowl, combine breadcrumbs and milk. Let sit 2–3 minutes until softened.
Mix the meatball base: Add ground meat, egg, Parmesan, onion, garlic, parsley, Italian seasoning, salt, and pepper to the breadcrumb mixture.
Stir gently with a fork or your hands until just combined. Don’t overmix or the meatballs can turn dense.
Form the meatballs: Lightly oil your hands and roll into 1.25–1.5-inch balls (about 16–18 meatballs). Brush or toss with 1 tablespoon olive oil for better browning.
Air fry in batches if needed: Arrange meatballs in a single layer in the air fryer basket. Cook at 380°F (193°C) for 10–12 minutes, shaking the basket halfway.
They’re done when internal temperature reaches 165°F (74°C) and they’re browned.
Make the sauce while they cook: Warm 1 tablespoon olive oil in a skillet over medium heat. Add sliced garlic and cook 30–45 seconds until fragrant (not brown). Pour in crushed tomatoes, sugar, oregano, and red pepper flakes.
Simmer 8–10 minutes. Season with salt and pepper, and stir in fresh basil.
Combine and serve: Add the cooked meatballs to the sauce and simmer 2–3 minutes to coat. Serve over pasta, stuff into toasted rolls, or spoon over polenta or rice.