Pat the fish dry. Use paper towels to remove surface moisture from the fillets. Dry fish helps the coating stick and crisp.
Preheat the air fryer. Set it to 400°F (200°C) for at least 5 minutes. A hot basket helps the crust set immediately.
Set up a breading station. In one shallow bowl, mix flour, 1/2 teaspoon salt, pepper, garlic powder, paprika, and onion powder.
In a second bowl, whisk eggs with Dijon. In a third bowl, combine panko, fine breadcrumbs, and lemon zest.
Season the fish lightly. Sprinkle the remaining 1/2 teaspoon salt over the fillets so they’re seasoned under the crust.
Dredge and coat. Work one piece at a time: toss in the seasoned flour, shake off excess; dip in egg, letting the extra drip off; press into the breadcrumb mixture to coat all sides. Press gently so the crumbs adhere.
Oil the basket and the fish. Lightly spray the air fryer basket.
Place coated fillets in a single layer with space between them. Lightly mist the tops of the fillets with oil spray for even browning.
Air fry until crisp. Cook at 400°F (200°C) for 8–12 minutes, flipping once halfway through and spraying again lightly. Fish is done when the coating is deep golden and the internal temp reaches 145°F (63°C) or flakes easily with a fork.
Finish and serve. Sprinkle with a little extra salt and a squeeze of lemon.
Serve hot with tartar sauce, lemon wedges, and a fresh salad or fries.