Preheat your air fryer to 400°F.
Slice the russet potato into thin wedges, toss them in a bowl with olive oil and a pinch of sea salt, and air fry for 15-18 minutes until golden and tender.
While the potatoes cook, whisk together the flour, baking powder, garlic powder, paprika, sea salt, and black pepper in a medium mixing bowl.
Slowly pour the light beer into the flour mixture, whisking continuously until a smooth, thick batter forms.
Pat the cod fillets thoroughly dry with paper towels to ensure the batter sticks properly.
Dip each cod fillet into the beer batter, allowing any excess to drip off before placing them into the air fryer basket.
Lightly spray the basket with oil and cook the fish at 375°F for 10-12 minutes, flipping halfway through, until the exterior is brown and crispy.
Serve the hot battered fish immediately with the potato wedges and a side of fresh greens if desired.