The cornstarch keeps moisture away from surface, which helps them to get crispy. If there was moisture from being drawn out, they’d be more soggy than crispy. It’s used a lot on wings in air, but usually they have so much oil in them they’ll get a little crispy anyway, best if you want really crispy. Which I don’t and love a tender wing not chicken jerky.

I’ve been trying to create one, but I so far don’t love how they turn out. My favorite onion rings are the kind that are battered, with the thick and chewy coating (the same coating I use on my fish and chips). That wet batter doesn’t work well in the air fryer. But if you like the crispy, breadcrumb style coating on your onion rings, that method will work! Here’s a recipe that looks great: https://www.spendwithpennies.com/air-fryer-onion-rings/