Place crappie fillets in a bowl. Add salt and water to cover. Cover and let sit to draw out all the blood, about 30 minutes. Rinse fillets thoroughly to remove salt. Pat dry with paper towels.
Preheat the air fryer to 400 degrees F (200 degrees C) according to manufacturer's instructions.
Add cornmeal, flour, seasoned salt, paprika, pepper, and cayenne to a gallon-sized zip-top bag. Seal and shake until evenly combined. Drop 2 fillets into the bag, seal, and shake to coat. Transfer to a plate. Repeat with remaining fillets.
Spray the tops of the fillets with nonstick cooking spray. Place a layer of fillets in the air fryer basket, sprayed-side down, making sure none are overlapping. Spray the tops with cooking spray. Cook for 4 minutes. Carefully flip and spray any chalky spots. Cook until crispy, about 4 minutes more. Repeat with remaining fillets.