Preheat the air fryer to 200°C (400°F).
Pat the ribeye steaks dry with paper towels.
Season both sides of the steaks evenly with 1/2 teaspoon salt and 1/2 teaspoon black pepper.
Rub the softened tablespoon of butter over both sides of each steak.
Place the steaks in the air fryer basket in a single layer and cook for a total of 12 minutes, flipping once halfway through cooking.
Cook to your preferred doneness: about 12 minutes for medium-rare (internal 135°F), longer as needed to reach 145°F for medium, 155°F for medium-well, or 165°F for well done.
Remove the steaks and let them rest for 2 minutes before serving.