In a small saucepan, melt the butter over medium heat. Then increase the heat to medium-high and add the miso paste, honey and rice wine vinegar. Stir until all ingredients are fully combined and bring the mixture to a boil. Remove it from the heat and set aside.
Place the bacon in the air fryer in a single layer (don't overlap!) and fry for 3-4 minutes on each side. Using a pastry brush, brush a thin layer of the miso glaze over one side of the bacon and air fry for 1 additional minute. It should be crispy and sticky when it's finished.
Notes
To catch the bacon grease, you can either line the bottom basket with foil or place a slice of bread at the bottom.