Pat the 4 6 ounce cod fillet dry with paper towels. This will help the seasoning stick and ensure a crisp finish.
In a small bowl, combine 1 1/2 tablespoon smoked paprika, 1 tablespoon garlic powder, 1 tablespoon onion powder, 1 tablespoon thyme, 1 tablespoon oregano, 1/2 teaspoon cayenne pepper, 2 teaspoons kosher salt, and 1 teaspoon black pepper. Rub both sides of each cod fillet with 2 teaspoons olive oil, then sprinkle generously with the seasoning mix.
Preheat the air fryer to 400°F (200°C) for 3-5 minutes.
Place the seasoned cod fillets in a single layer in the air fryer basket. Cook at 400°F for 8-10 minutes, or until the fish is cooked through and flakes easily with a fork. Check for an internal temperature of 145°F (63°C).
Remove the cod fillets from the air fryer and serve with your favorite sides like roasted vegetables, a fresh salad, or rice.