Prep your pan and air fryer. Line a 6-inch loaf pan with parchment and lightly spray the sides. Preheat the air fryer to 320°F (160°C) for 3–5 minutes. Preheating helps the loaf rise evenly.

Mash the bananas. In a large bowl, mash the ripe bananas until mostly smooth with a few small lumps. You should have about 1 1/4 cups.

Add the wet ingredients. Stir in the melted butter, granulated sugar, brown sugar, egg, and vanilla. Mix until combined but don’t whip.

Whisk the dry ingredients. In a separate bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon (if using).

Combine gently. Add the dry ingredients to the banana mixture. Fold with a spatula until just combined. A few streaks of flour are okay. Do not overmix.

Add mix-ins. Fold in nuts or chocolate chips if you’re using them. Keep it to about 1/2 cup so the loaf doesn’t get heavy.

Fill the pan. Scrape the batter into the prepared pan and smooth the top. If you like, sprinkle a little sugar or extra nuts on top for texture.

Bake in the air fryer. Place the pan in the basket. Cook at 320°F (160°C) for 28–38 minutes, depending on your air fryer and pan size. Start checking at 28 minutes. The bread is done when a toothpick comes out with a few moist crumbs.

Tent if needed. If the top is browning too quickly before the center is set, gently place a small piece of foil over the loaf and continue cooking.

Cool before slicing. Let the bread cool in the pan for 10–15 minutes, then lift it out using the parchment and move to a rack. Cool at least another 15 minutes before slicing for cleaner cuts.