To cook frozen French fries, remove them from the freezer and without thawing them pour them into the air fryer basket. Make sure you evenly spread them over the basket. Set the temperature of the air fryer to 400 degrees Fahrenheit and the timer to 15 minutes. After about 5-7 minutes into the frying, remove the basket, gently shake it, then gently run the fries and return into the fryer and continue cooking. For a crispier and crunchier surface, add at least 2 to 3 extra minutes of cooking and turn them more than once.