01 - Peel the bananas and cut them into thin, even slices about 1/8 inch thick for consistent cooking.
02 - Combine the granulated sugar and ground cinnamon in a small bowl until evenly blended.
03 - Brush both sides of the banana slices lightly with melted coconut oil, then sprinkle with the cinnamon sugar mixture on both sides.
04 - Place the coated banana slices in a single layer in the air fryer basket, working in batches if necessary to prevent overlapping.
05 - Air fry at 350°F for 10-15 minutes, flipping the chips halfway through. Monitor closely during the final minutes to prevent burning.
06 - Transfer the chips to a wire rack to cool completely; they will continue to crisp up as they cool. Optionally sprinkle with sea salt before serving.