If necessary, remove the silver skin from the meat. Then pat the tenderloin dry with paper towels and plate onto a plate.
Mix the olive oil, parsley, onion powder, garlic powder, salt, thyme, and pepper in a small bowl. Spread the marinade evenly all over the meat. This works best if you massage it in with your hands
Place the tenderloin into your air fryer basket (bend it to fit, don't cut it), and cook at 400 degrees F for 15-20 minutes. (see note)
Let the meat rest for 5 minutes on a cutting board before slicing. Don´t throw away the juices that collect in the air fryer, you can drizzle them over the meat for serving. It's delicious!
Notes
The cooking time depends on the thickness of the meat and on how cooked you like it. Pork is safe to eat at 145 degrees F, but some like it better at 160°F. Try to not cook it more than 160 degrees F to avoid dryness.