Pat the salmon fillet dry with paper towels, making sure to remove excess moisture from both the skin and flesh—this helps the seasoning stick and creates better browning in the air fryer. While the salmon dries, combine the olive oil, soy sauce, honey, lemon juice, and 1/2 tsp garlic powder in a small bowl, whisking until the honey is fully dissolved and incorporated. I find that slightly warming the honey first (even just letting it sit in warm water for a minute) makes it dissolve more smoothly into the glaze.
Season the dried salmon fillet on all sides with salt, black pepper, and 1/8 tsp garlic powder. Place the seasoned salmon skin-side down in a shallow dish or on a plate, then pour the glaze from Step 1 over the top, using a brush or spoon to coat the flesh evenly. Let the salmon sit in the glaze for about 5 minutes—this allows the flavors to begin penetrating the fish while the oil helps it develop a nice glaze during cooking.
Transfer the glazed salmon to your air fryer basket, skin-side down, and cook at 390°F for 7-8 minutes. The salmon is done when the flesh is opaque and flakes easily with a fork—I always check for doneness at the thickest part first, as that's the last area to cook through. The skin will crisp up beautifully while the glaze caramelizes slightly, creating a sweet and savory crust.