To mellow the sharpness of the onion, sauté it in a tablespoon of butter until soft, then allow to cool before incorporating. Avoid overmixing the meat to maintain a tender texture. Always preheat the air fryer prior to cooking. Due to variations among air fryer models, it's crucial to use a thermometer to ensure doneness. Monitor cooking closely to avoid overcooking. Letting the meatloaf rest helps it maintain its shape when cut. Store leftovers in a sealed container in the fridge for up to four days.