Grease an (8x4-inch) loaf pan with cooking spray and then dust it with a little flour. Set aside.
In a bowl, mix together the flour, baking powder, baking soda, cinnamon, and salt.
In another large bowl, add the sugar, oil, eggs, and vanilla extract and beat until well combined.
Add in the flour mixture and stir until just combined.
Gently, fold in the zucchini and walnuts.
Place the mixture into the prepared loaf pan evenly.
Slide the Air Fryer Basket inside and adjust the temperature to 320 °F to preheat for 5 minutes.
After preheating, arrange the loaf pan into the Air Fryer Basket.
Slide the basket into Air Fryer and set the time for 20 minutes.
After cooking time is finished, remove the loaf pan from Air Fryer and place onto a wire rack for about 10 minutes.
Carefully remove the bread from pan and place onto the wire rack to cool completely before slicing.
Cut the bread into desired-sized slices and serve.