Set the unit to Air Fry at 400˚F. Peel the sweet potatoes and cut them into fry-shaped pieces about 1⁄4 inch wide and 1⁄4 inch thick.
Try to cut them into similarly sized pieces so the fries will bake evenly.
Sprinkle the sweet potato fries with the cornstarch (1 1⁄2 teaspoons) and salt (1⁄4 teaspoon). Toss until the fries are lightly coated in powder. Drizzle the olive oil over the fries (1 tablespoon) and toss until the fries are lightly and evenly coated in oil, and no powdery spots remain.
Arrange fries in a single layer and don’t overcrowd. Air fry for 10 minutes, then flip the fries so they can cook on all sides. Arrange the fries in an even layer. Bake for 10 more minutes, or until the fries are crispy.
You’ll know they’re almost done when the surface of the fries change from shiny orange to a more matte, puffed up texture. Keep an eye on them, as they can turn from crisp to burnt quickly.