Prep the asparagus. Cut or snap off the tough, woody ends from the asparagus spears (usually about 1 to 2 inches). Drizzle with olive oil and sprinkle with kosher salt and pepper; toss to coat.
Air fry. Arrange the asparagus in the air fryer. A single layer is best, but the spears can overlap a bit. Fry at 400°F for 5 to 7 minutes, depending on thickness, shaking the basket several times to cook them evenly.
Finish the dish. Transfer the asparagus to a serving plate and drizzle with lemon juice. Garnish with freshly grated Parmesan cheese and serve with lemon wedges.