Preheat the air fryer to 400°F.
Peel the sweet potatoes and cut them into thin fries, about 1/4 inch thick.
In a large bowl, toss the sweet potato fries with olive oil, paprika, garlic powder, onion powder, salt, black pepper, and cornstarch if using. Make sure the fries are evenly coated.
Place the sweet potato fries in a single layer in the air fryer basket. You may need to do this in batches depending on the size of your air fryer.
Cook for 15-20 minutes, shaking the basket halfway through to ensure even cooking.
Check for desired crispiness; if needed, cook for an additional 2-3 minutes.
Once done, remove the fries from the air fryer and let them cool slightly before serving.
Enjoy with your favorite dipping sauce.