Preheat your air fryer to 350°F (175°C).
Peel the bananas and slice them into thin rounds, about 1/8 inch thick.
In a large bowl, toss the banana slices with lemon juice to prevent browning.
In a separate small bowl, mix together the sugar, cinnamon, and salt.
Drizzle the melted coconut oil over the banana slices and toss to coat evenly.
Sprinkle the cinnamon sugar mixture over the bananas and toss again until well coated.
Arrange the banana slices in a single layer in the air fryer basket. You may need to do this in batches depending on the size of your air fryer.
Air fry the banana slices for 10-12 minutes, flipping halfway through, until they are golden brown and crispy. Keep an eye on them to prevent burning.
Once done, remove the chips from the air fryer and let them cool for a few minutes before serving.