To cook frozen fries using the air fryer is pretty simple. All you need to do is to simply preheat the air fryer at a temperature of 400°F for about 10 to 15 minutes then add the frozen fries. Simple as that. If you are wondering if you need to thaw the frozen fries first, the answer to that is no. You no longer need to thaw the frozen fries as the hotness in the air fryer will cook the fries until it is crispy.