Trim woody ends off of the asparagus - you can cut them or snap the ends and where the asparagus breaks off naturally is where the woody end starts
Toss asparagus in oil and salt. Place the asparagus in the air fryer basket in an even layer - you may need to cook it in 2 batches.
Cook at 400F for 6 minutes - sprinkle the parmesan cheese on top, if cooking in batches use only half the cheese per batch. Cook for another 2-3 minutes in the air fryer.
You can keep the first batch warm in the oven at 175F while you cook the second batch. Serve immediately with a squeeze of lemon
Notes
You can store leftovers in the fridge for up to 4 days.