01 - Preheat air fryer to 400°F for 5 minutes to ensure optimal crisping.
02 - Separate onion slices into individual rings. Discard small centers or reserve for other uses.
03 - Arrange three shallow bowls. Combine flour, garlic powder, smoked paprika, salt, and black pepper in the first. Whisk eggs and milk in the second. Place panko breadcrumbs in the third.
04 - Dredge each onion ring in flour mixture, shaking off excess. Dip into egg mixture, then press firmly into panko crumbs to coat evenly.
05 - Place coated rings in single layer in air fryer basket. Lightly mist tops with cooking spray. Work in batches to avoid overcrowding.
06 - Cook at 400°F for 10-12 minutes, flipping rings halfway through cooking time, until golden brown and crispy.
07 - While rings cook, whisk mayonnaise, minced chipotle pepper, adobo sauce, lime juice, and salt in small bowl until smooth. Taste and adjust seasoning.
08 - Transfer hot onion rings to serving platter. Accompany with chipotle mayo for dipping. Serve at once while crispest.