Prepare the sprouts by trimming stems and cutting into uniform halves or quarters. Pat completely dry to remove moisture.
Toss sprouts with 1½ to 2 teaspoons oil and salt; add pepper and optional seasoning now if using.
Preheat air fryer to 375-400°F (190-204°C) for 3 to 5 minutes to ensure immediate crisping.
Cook sprouts in a single layer for 12 to 15 minutes, shaking basket every 5 minutes until edges are golden and interiors tender.
Add finishing touches with lemon juice or balsamic vinegar and sprinkle Parmesan or herbs while hot.