Preheat the air fryer to 400°F for 3 minutes.
Pat the asparagus spears completely dry with paper towels, then place in a large bowl and toss with olive oil until evenly coated.
Sprinkle the Parmesan cheese, garlic powder, salt, and pepper over the asparagus and toss again to distribute evenly.
Arrange asparagus in a single layer in the air fryer basket, working in batches if necessary to avoid overcrowding.
Air fry for 6-8 minutes, shaking the basket halfway through, until the asparagus is tender and the Parmesan is golden and crispy.
Serve immediately while hot and crispy.