Put a sheet of parchment paper (with holes) in the bottom of the air fryer. You can make this without parchment paper, but it simplifies cleanup and keeps the salmon skin from sticking to the basket.
Transfer the salmon fillets to the air fryer basket, skin side down. Cook at 400 degrees F for 8 minutes. There is no need to flip the salmon during the cooking time.
Check the salmon by testing it with a fork. If it is pinkish opaque colored and flakes easily it is done. Alternately, you can use an instant read thermometer. The salmon is done at 145 degrees F.
If it isn't done air fry it at 400 F for another 1-2 minutes until it is done.
Notes
Cooking time will vary based on your air fryer and the thickness of the salmon. I used salmon just under an inch thick and cooked it in my 5.8 quart Corsori air fryer.Change up the seasoning for different flavors. Other seasoning ideas include Cajun seasoning, lemon pepper, seasoned salt or Old Bay.If you are cooking frozen fillets increase the cooking time to 12-15 minutes. I would suggest using an instant read thermometer for frozen fillets instead of relying on the fork test. I prefer to thaw the salmon before cooking it.