Preheat the air fryer to 400 degrees F.
Rinse and scrub the potatoes, then thoroughly dry them with a paper towel.
Rub the skin with olive oil and sprinkle them with salt (and pepper, if using).
Air fry the potatoes at 400 degrees F for 40-50 minutes, using tongs to flip them once halfway through the cooking time. They are done cooking when pierced easily with a fork.
