Preheat the air fryer to 375°F (190°C).
In a mixing bowl, combine the cubed apples, sugar, cinnamon, and melted butter. Toss well to coat evenly.
Spread the apples in an even layer in the air fryer basket.
Cook for 10-12 minutes, shaking the basket halfway through, until the apples are tender and slightly caramelized.
Serve warm, optionally topped with whipped cream or vanilla ice cream.