Stir together panko, cayenne pepper, ½ teaspoon of salt and ½ teaspoon of black pepper in a pie plate. Stir together melted butter, ½ teaspoon salt, and ¼ teaspoon of black pepper in a small bowl, then brush all over chicken. Add chicken two pieces at a time, to crumb mixture and coat evenly on both sides, pressing chicken into crumbs to help them adhere, then transfer onto 4-inch rack. Air fry chicken on power level high for 15 minutes per side. For thicker chicken breasts. 7-8 minutes for thinner chicken breasts. Let chicken rest with dome on for 1-2 minutes.