Every air fryer is different both in capacity and in temps. You may want to do this in smaller batches depending on the size of the air fryer you’re using. I use this air fryer.
If the broccoli overlaps in the basket a bit at first, that’s okay – it’ll reduce in size to eventually make a single layer for the last few minutes of roasting.
If you’re doing that final roast at 375 and not getting enough crisping, go up to 390!
If you don’t have a basket air fryer, that’s fine! Massage the water and oil into the broccoli florets in a separate bowl for a minute before placing them on the tray. I almost think of this as “marinating” the broccoli with some moisture. The broccoli will hold onto that moisture (even if it doesn’t absorb it completely) and it helps keep it tender while roasting. 
