Peel and dice one fresh apple into small, even pieces. Set aside.
In a mixing bowl, crack in 2 large eggs and whisk them gently. Add 1/4 cup of milk, 1 teaspoon of vanilla extract, 1 teaspoon of ground cinnamon, and 1 tablespoon of sugar. Whisk all ingredients together until smooth and well combined. Stir in the diced apples gently.
Take 4 slices of bread and cut each into 3 or 4 sticks, depending on your preferred size.
Dip each bread stick into the custard mixture, soaking for about 20 seconds. Ensure each stick is fully coated but not overly saturated.
Preheat your air fryer to 375°F (190°C) for about 3 minutes. Lightly spray the air fryer basket with cooking spray.
Place the soaked bread sticks in a single layer in the air fryer basket without overlapping. Air fry for 8-10 minutes, flipping halfway through, until golden brown and crispy.
Remove the French toast sticks from the air fryer and serve immediately. Enjoy with maple syrup, honey, or a sprinkle of powdered sugar.