In a bowl, combine half of the flour, cornflour and baking powder. 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 second half of the flour with paprika, salt, black pepper in a large bowl. in a shallow dredging pan.
Pat the 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.
Preheat the air fryer to 390°F.
Generously spritz both sides of the coated fish fillets with vegetable oil and place them in the air fryer basket. Air-fry for 12 minutes at 190˚C/380ºF. Spritz with more oil during the cooking process if there are any dry spots on the coating.
Serve immediately with lemon wedges and why not some air-fried French fries and coleslaw too!