Preheat your air fryer to 350 degrees F, if your model calls for preheating.
Drain the peaches or peel and slice if you are using fresh peaches and put them in a large bowl.
Add the brown sugar, cinnamon and cornstarch to the waiting peaches. Toss until the peaches are well-coated.
Grease the bottom and sides of two 6- inch cake rounds (check that your baking pan will fit into your air fryer first) with butter or nonstick cooking spray.
Spoon the peach mixture into the baking pan.
To make your topping, place the flour, brown sugar and cinnamon in a large mixing bowl and cut in the butter with a pastry blender or pulse in a food processor, until well-blended.
Sprinkle the crumb mixture on top of the peaches.
Cover the pans with aluminum foil and place the pan in the air fryer.
Bake at 350 degrees F for 15 minutes.
Carefully take the aluminum foil off and bake for another 10 or 15 minutes, or until the top is lightly browned and the peach layer is bubbling slightly.
Carefully remove the pan from the air fryer and let cool for 5-10 minutes. Serve warm with vanilla ice cream or whipped topping, optional.