Start by peeling the bananas and then slice them into uniform 1/8-inch thick rounds. Using a mandoline slicer is recommended for consistency.
Warm up your air fryer to 330°F (165°C). To prevent sticking, you can lightly coat the basket with cooking spray.
In a small bowl, thoroughly combine the sugar and ground cinnamon to create the topping.
Transfer the banana slices to a larger bowl, sprinkle the cinnamon-sugar mix over them, and toss gently until each slice is lightly coated.
Place the coated banana slices in the air fryer basket in a single layer, ensuring they do not overlap. Air fry for 10-14 minutes, flipping the slices at the halfway point.
The chips are done when they appear golden brown and feel crisp. Your specific air fryer model may require slight adjustments to the cooking time.
Move the finished banana chips to a wire rack to cool. They will become significantly crispier as they rest for 5-10 minutes.