Wash and dry broccolini. Trim bottom ½ inch of stem.
Drizzle with olive oil and season with salt and pepper. Toss.
Add to air fryer basket in a single layer. Air fry at 380 degrees for 6-9 minutes, checking at the 5 minute mark for doneness.
Remove from the air fryer and plate. Top with crumbled feta and fresh lemon zest. Serve with lemon halves for squeezing.
Notes
All air fryers cook differently. Watch broccolini closely to make sure it doesn't burn. This is why I suggest starting to check around the 5 minute mark, even though it usually takes a bit longer.
If a few of your broccolini pieces have very thick stems, you can cut them in half lengthwise to make sure they all cook evenly and that the stems get tender when cooking.