In a large mixing bowl, whisk the ingredients for the buttermilk marinade together and place the chicken cutlets into the bowl, submerging them completely. Put them in the fridge for at least an hour, up to overnight.
In a shallow bowl or pie plate, mix together the panko breadcrumbs, onion powder, garlic powder, Italian seasoning, white pepper, and cayenne pepper; set aside.
Make the honey mustard sauce! Mix all of the ingredients in a small bowl. Cover, and place it in the fridge until dinner time.
When you're ready to cook the chicken, preheat the air fryer to 390º F. Spray the bottom of the air fryer basket with some cooking spray.
Create an assembly line with a shallow bowl of flour, egg wash, and breading mixture. One at a time, take a chicken cutlet from the buttermilk bath and gently shake off any excess buttermilk. Dredge the chicken cutlets into the flour, then the eggs, and finally the crumbs. Place the breaded cutlets into the air fryer basket once it's done preheating. You will probably have to do this in two batches, depending on how many cutlets you can fit into the air fryer.
Cook the cutlets for 5 minutes. When 5 minutes is up, carefully flip them over and give the basket and the cutlets a mist with the cooking spray. Cook for another 5 minutes.
When done, serve with honey mustard sauce.