Trim about 1 to 2 inches (2.5 to 5 cm) off the ends of the asparagus and carefully place them inside your air fryer basket.
Toss to coat evenly then air fry at 400°F (200°C) for 7-9 minutes, shaking the basket halfway through, until the asparagus is crispy on the outside, and tender on the inside.
Once cooked, transfer to a plate, squeeze lemon juice over the asparagus, and sprinkle with extra Parmesan cheese. Serve immediately.