Remove the pork loin from its packaging and pat it completely dry with paper towels. Let it sit at room temperature for 30 minutes to take the chill off.
Preheat your air fryer to 400°F (200°C) for 5 minutes. Cut a piece of parchment paper to fit the bottom of your air fryer basket.
Score the fat cap of the pork loin with a sharp knife in a crisscross pattern, being careful not to cut into the meat itself.
Place the pork loin fat-side down on a cutting board. Rub the meat with half of the olive oil, then season it evenly with half of the salt and all of the black pepper.
Flip the pork over so the fat side faces up. Rub the remaining olive oil over the top and sprinkle with the remaining salt, rubbing it into the score marks.
Place the parchment paper in the preheated air fryer basket and set the pork loin on top, fat-side up. Air fry at 400°F (200°C) for 20 minutes.
Check the pork. If it is browning unevenly, rotate the roast in the basket. Cook for another 20 to 30 minutes.
Check the thickest part of the meat with an instant-read thermometer. It is safe to eat when it reaches 145°F (63°C).
Transfer the pork to a cutting board and let it rest for at least 3 minutes before slicing and serving.