Preheat oven to 350°F (175°C) and grease a loaf pan.
In a bowl, whisk together flour, baking powder, baking soda, cinnamon, nutmeg, and salt.
In another bowl, mash the bananas and mix in the pumpkin puree.
Add sugar, brown sugar, eggs, vanilla extract, and vegetable oil to the banana-pumpkin mixture and mix well.
Gradually fold in the dry ingredients, stirring until just combined.
Optional: Fold in chocolate chips or chopped nuts for added texture.
Pour batter into the prepared loaf pan and spread evenly.
Bake for 55-65 minutes, or until a toothpick inserted into the center comes out clean.
Let the loaf cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.