Peel and slice the onions into 2-inch rounds and separate them to make an individual onion ring (i.e., so that there is only 1 layer of the onion).
In one bowl whisk the eggs together. In another bowl mix the flour, garlic, onion powder, salt, and pepper together, and in a third add the panko crumbs. Line them up so that you can go from one to the next easily.
Preheat your air fryer to 350°F.
Dip the onion ring in the flour, then in the egg, then in the panko crumbs. You can dip them in the flour and egg mixture twice if you would like them quickly and thickly coated.