Preheat your air fryer to 400°F (200°C) for about 3 minutes.
Pat the salmon fillets dry with a paper towel.
Rub each fillet with olive oil, then season both sides with garlic powder, paprika, salt, and pepper.
Place the fillets skin-side down in the air fryer basket.
Cook for 7–10 minutes depending on the thickness of the salmon, or until it flakes easily with a fork.
Remove carefully, squeeze lemon over the top if using, and serve immediately.