Preheat the oven to 350 degrees {Fahrenheit}.
Grease the sides and bottom of an 8 1/2-by-4 1/2 inch loaf pan.
Place the coconut oil, eggs, honey, vanilla, and vinegar in the bowl of a stand-up mixer and beat on high for 30 seconds.
Combine the coconut flour, oat flour, baking soda, and sea salt in a bowl. Add them to the wet ingredients, beating until combined.
Place the milk, and bananas in a separate bowl and mash.
Add the banana mixture to the batter and beat until well combined.
Mix in the optional chocolate chips {reserving a few to sprinkle on the top, if desired}.
Pour the batter into the prepared loaf pan and bake for approximately 40-45 minutes, until a toothpick inserted in the center comes out clean.
Remove from the oven and cool in the loaf pan for 20 minutes. Slice and serve! {The banana loaf is delicious refrigerated and served a day or two after it was made, as well!}