Coat an 8-inch silicone air fryer tray with cooking spray.
In a mixing bowl or measuring cup, vigorously whisk the eggs and milk until the mixture is frothy and airy.
Stir in the chopped ham, spinach, green onion, and grated cheddar cheese, then season with salt and pepper and combine thoroughly.
Pour the egg mixture into the prepared silicone tray, smoothing it out evenly with a fork, then arrange the cherry tomato slices on top.
Preheat your air fryer to 340°F (170°C) for a few minutes.
Carefully remove the air fryer basket, place the filled silicone tray inside, and return the basket to the air fryer.
Cook the omelette in the air fryer for 9 to 12 minutes.
After 9 minutes, check doneness by gently lifting the edge; if it’s still runny, return it to cook for an additional 2 to 3 minutes until fully set.
Take the tray out of the air fryer and set it on a heat-resistant surface.
Use a spatula to carefully loosen and slide the omelette onto a plate without breaking it.
Serve warm alone or with your favorite breakfast accompaniments.