Prep the pan and air fryer. Lightly grease your pan and line the bottom with parchment. Preheat the air fryer to 310°F (155°C) for 3–5 minutes. A slightly lower temperature prevents over-browning.
Mash the bananas. In a large bowl, mash the ripe bananas with a fork until mostly smooth.
A few small lumps are fine and add texture.
Whisk in wet ingredients. Add the oil (or melted butter), granulated sugar, brown sugar, eggs, and vanilla. Whisk until the mixture looks glossy and combined.
Combine dry ingredients. In a separate bowl, whisk the flour, baking soda, baking powder, and salt. If using cinnamon, add it here.
Mix gently. Add the dry ingredients to the wet.
Stir with a spatula just until you no longer see dry flour. Do not overmix—that can make the bread tough.
Fold in add-ins. If you’re using nuts or chocolate chips, fold them in now. Save a few to sprinkle on top for a nice finish.
Fill the pan. Pour the batter into the prepared pan and smooth the top. The pan should be about 2/3 full to allow room for rising.
Air fry. Place the pan in the basket.
Cook at 310°F (155°C) for 35–45 minutes. Check at 30 minutes to gauge browning. If the top is getting dark too fast, tent loosely with foil and continue.
Test for doneness. Insert a toothpick in the center.
It should come out with a few moist crumbs but no wet batter. If needed, continue cooking in 3–5 minute increments.
Cool properly. Let the bread cool in the pan for 10–15 minutes, then lift it out and cool on a rack for at least 30 minutes before slicing. This helps it set and stay moist.