Combine the 1 cup of flour, cornstarch and baking soda in a large bowl. Add the beer and egg and stir until smooth. Cover the bowl of batter with plastic wrap and refrigerate for at least 20 minutes.
Combine the ¾ cup of flour, paprika, salt, black pepper and cayenne pepper in a shallow dredging pan.
Make sure your pieces of fish are at least 1 to 1½ inches thick so they don't dry out in the air fryer. Pat the cod fish fillets dry with a paper towel. Dip the fish into the batter, coating all sides. Let the excess batter drip off and then coat each fillet with the seasoned flour. Sprinkle any leftover flour on the fish fillets and pat gently to adhere the flour to the batter.
Pre-heat the air fryer to 390°F.
Generously spritz both sides of the coated fish filets with vegetable oil and place them in the air fryer basket. Air-fry for 12 minutes at 390ºF. Spritz with more oil during the cooking process if there are any dry spots on the coating.
Serve immediately with lemon wedges, malt vinegar and tartar sauce. It’s perfect with some air-fried French fries and coleslaw too!