Take string cheese sticks and cut them in half to create perfectly sized mozzarella sticks.
Set up three shallow bowls: mix flour and cornstarch in the first; beaten eggs in the second; combine breadcrumbs, Parmesan cheese, garlic powder, onion powder, oregano, basil, salt, and pepper in the third.
Dip each mozzarella stick half into the flour mixture, then beaten eggs, and finally the breadcrumb mixture, pressing gently to coat well.
Preheat the air fryer to 390°F (200°C).
Lightly spray the air fryer basket with cooking spray. Place breaded sticks in a single layer, spray tops lightly with cooking spray.
Air fry for 6-8 minutes, flipping halfway through, until golden brown and crispy.
While cooking, heat olive oil in a small saucepan over medium heat, sauté minced garlic for about 1 minute. Add marinara sauce, oregano, basil, salt, and pepper; stir and simmer until heated through.
Remove mozzarella sticks from air fryer, let cool slightly, and serve hot with marinara sauce for dipping.