How to cook fried potatoes in a No Fry Cooker?
The reason to spread out oven fries into a single layer is to remove moisture from them more effectively, so they don't end up soggy. An air fryer's convective heating is much more effective at removing moisture, even compared to a convection oven. So piling them up doesn't cause much of a problem. If your air fryer doesn't have a stirring arm, you should still stir or shake the fries partway through cooking, to ensure even browning and avoid soggy spots.