Preheat the air fryer to 350 degrees F (175 degrees C).
In a large bowl, combine the beef, salt, onion powder, garlic powder, egg, 3 tablespoons of the Parmesan, and the bread crumbs. Mix well until evenly combined. Using an ice cream scoop or your hands, form into 6 equally-sized meatballs. Place them in the air fryer, and cook for 10 minutes, flipping halfway through. Transfer to a plate, cover, and set aside.
Meanwhile, bring a pot of water to a boil and cook the pasta according to the package directions. In a small saucepan over medium heat, combine the tomato sauce, onion powder, garlic powder, Italian seasoning, salt, and pepper. Bring to a simmer, reduce the heat to low, and cook for 5 minutes.
Serve the spaghetti, with the marinara, 3 meatballs, and the remaining parmesan.