In a medium-sized mixing bowl, combine the flour, garlic powder, and ground black pepper. Stir well until all dry ingredients are evenly mixed to ensure every bite is flavorful.
Preheat the air fryer to 350° F so it's ready to create that perfect crispy texture when you add the banana peppers.
Dip each sliced banana pepper into the seasoned flour mixture, ensuring they are well-coated. Allow them to sit for about 5 minutes; this helps achieve a thick layer of flour on each pepper.
Place the coated banana peppers in a single layer in the air fryer basket. Be careful not to overcrowd them as this can affect their crispiness.
Spray cooking oil over both sides of the banana peppers generously before cooking. This step is crucial for achieving that golden-brown finish.
Air fry the banana peppers for approximately 8 minutes or until they turn golden brown and crispy. Once done, transfer them onto a baking sheet lined with paper towels to absorb any excess oil before serving.