In a medium bowl, combine flour, cornstarch, baking soda, and salt.
In a large bowl stir together the butter and both sugars until well combined. Add in the egg and vanilla. Mix well.
Add the dry ingredients to the wet ingredients, and gently fold in the chocolate chips.
Place dough in the refrigerator and chill for 30 minutes.
Preheat the Air Fryer to 300°F on the BAKE setting.
Use an ice cream scoop to portion out about 3 tablespoons of dough per cookie. Place the cookie dough in the air fryer basket, making sure to leave 2 inches of space between each cookie. If needed, bake the cookies in batches.
Flatten the cookies to approximately 1/2" thickness using a glass or measuring cup. This ensures even baking.
Bake the cookies for 10-13 minutes. They will still be soft when done. Allow the cookies to cool completely, as they will firm up and become chewy in the center.
Notes
Make uniform cookie portions so they bake at the same rate.
Evenly space to allow enough air to circulate between them for the best results.
Air Fryer cookies will keep in an airtight container for a week.