The short answer is yes, you can technically put foil in an air fryer. However, putting the aluminum foil in the bottom of your air fryer basket can block the air circulation which can cause your food to be cooked unevenly. My personal recommendation: do not put foil in the basket of your air fryer. You don't want to limited the circulation of air needed to "fry" your food to perfection. Use these air fryer liners instead.