In a large mixing bowl, combine the ground beef, breadcrumbs, chopped onion, milk, egg, ketchup, Worcestershire sauce, garlic powder, salt, black pepper, and dried Italian seasoning. Mix well until all ingredients are thoroughly combined.
Shape the mixture into a loaf that fits in your air fryer basket. If using a loaf pan, press the mixture into the pan.
Preheat the air fryer to 360°F (182°C) for about 5 minutes.
Place the meatloaf in the air fryer basket (or the loaf pan inside the basket). Cook at 360°F for 25 minutes, or until the internal temperature reaches 160°F (71°C).
If desired, during the last 5 minutes of cooking, brush additional ketchup on top of the meatloaf for extra flavor.
Once cooked, remove the meatloaf from the air fryer and let it rest for about 5 minutes before slicing.