01 - Preheat air fryer to 400°F for 5 minutes to ensure optimal crisping.
02 - Separate onion slices into individual rings. Discard very small centers or reserve for another use.
03 - Prepare three shallow bowls: combine flour, garlic powder, smoked paprika, salt, and 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, allowing excess to drip off. Press firmly into panko breadcrumbs to coat evenly. Place on baking sheet.
05 - Arrange coated rings in single layer in air fryer basket, cooking in batches if necessary. Lightly spray with cooking spray. Air fry at 400°F for 10-12 minutes, flipping halfway through, until deep golden brown and crispy.
06 - While rings cook, combine mayonnaise, minced chipotle pepper, adobo sauce, lime juice, and salt in small bowl. Whisk until smooth. Taste and adjust seasoning with additional chipotle or salt as desired.
07 - Transfer hot onion rings to serving platter. Serve immediately with chipotle mayo alongside for dipping.