Peel the bananas and slice them into thin rounds, about 1/8 inch thick.
In a small bowl, mix together the granulated sugar and ground cinnamon.
Place the banana slices in a large bowl and drizzle with lemon juice, tossing gently to coat.
Sprinkle the cinnamon-sugar mixture over the banana slices and toss until evenly coated.
Preheat your air fryer to 350°F.
Lightly spray the air fryer basket with cooking spray to prevent sticking.
Arrange the banana slices in a single layer in the air fryer basket, making sure they do not overlap.
Air fry the banana slices for 10-12 minutes, shaking the basket halfway through to ensure even cooking, until they are golden and crispy.
Remove the banana chips from the air fryer and let them cool completely before serving.