Season salmon all over with salt and pepper.
In s small bowl, whisk together oil, mustard, maple syrup (or brown sugar), garlic and thyme. It should be a paste-like consistency.
Spread on top of the salmon fillet.
Preheat your air fryer to 425F for 5 minutes. This is an important step. You want to make sure your air fryer is hot and ready for the salmon.
Arrange salmon in air fryer basket or tray. Skin side down
Set air fryer to 400F/200C and cook for 6-8 minutes, depending on the size of the thickest piece of salmon fillet.
When the timer goes off, open the basket and check fillets with a fork to make sure they are done to your desired doneness.