Sure, you can cook them in the air fryer. They will turn out crispy and flavorful. You will need to use something to fold the taco shell so you can add fillings when it’s done cooking. If you have a metal taco maker, you can use that (if it fits in your air fryer). You can ball up aluminum foil and sandwich the tortilla shell around the foil. If you cook the shell flat, then you’ll have more like a dessert tostada instead.