Husk and thoroughly clean each corn cob. Divide into 3-4 bite-sized pieces (depending on the length of the corn) to create 1.5-inch pieces of corn.
Place the corn into an air fryer basket in a single layer. Spritz the corn with oil.
Cook on the air fryer setting at 400 degrees (preheat first if your model requires it) for 5 minutes.
Flip, spritz the underside with oil, and cook for an additional 5 minutes at 400 degrees. You may need an additional 1-2 minutes on each side to ensure a golden brown color. Mine took 13-14 minutes in total, rotating a few times throughout the cooking time.
Heat butter in a large bowl in the microwave until mostly melted, about 10-15 seconds from room temperature. Add in the cajun seasoning and whisk until smooth.
Add the corn directly from the air fryer into the large bowl of melted seasoned butter. Use a large spoon to toss them evenly to coat on all sides. It can be helpful to use a basting brush to get in the crevices of the corn.
Serve warm with ranch dressing for dipping.
