Peel the onions and slice into 1/2-inch thick rings. Gently separate the rings, keeping the larger outer rings and reserving the smaller inner pieces for another use. You should get about 12-16 good rings per onion.

In a shallow bowl, whisk together flour, garlic powder, paprika, 1/2 teaspoon salt, and black pepper. In a second bowl, beat the eggs. In a third bowl, place the panko breadcrumbs. Arrange the bowls in a line: flour, then eggs, then panko.

Working with 3-4 rings at a time, dredge in flour and shake off excess. Dip into the beaten egg, letting excess drip off. Press into panko to coat both sides, pressing gently so the crumbs adhere. Place coated rings on a plate or wire rack.

Preheat air fryer to 375F. Arrange onion rings in a single layer in the basket, making sure they do not touch. Lightly spray the tops with cooking spray. Air fry for 8 minutes, then flip, spray again, and cook 6-8 minutes more until deep golden and crispy.

Transfer hot onion rings to a serving plate and sprinkle with remaining 1/2 teaspoon salt while still warm. Serve immediately with your favorite dipping sauce.