Preheat your air fryer to 390°F (about 3 minutes). While it's warming up, pat the frozen salmon fillets with a paper towel to remove any ice crystals.
Lightly brush each salmon fillet with olive oil. Season with salt and pepper to taste. Add a sprinkle of dried dill or parsley if preferred.
Place the salmon fillets in the air fryer basket, skin-side down if they have skin. Air fry for 7 minutes. This initial stage thaws the fish and begins to gently cook it from the outside in.
After the first 7 minutes, pause the air fryer and top each fillet with a couple of thin lemon slices.
Return the basket to the air fryer and cook for an additional 3-7 minutes. The exact time will depend on the thickness of your fillets and how well done you prefer your salmon.