Sift together the flour, baking soda, cinnamon and salt. Beat sugar and eggs with a whisk until light and fluffy, about 10 minutes. Add in coconut oil. Mix in mashed bananas and vanilla. Stir in dry ingredients just until blended. Do not overmix.
Pour into a prepared loaf pan and bake for about 45 minutes to 1 hour. Check with a skewer or toothpick. It will come out clean. Cool on wire rack for 15 minutes. Remove from pan and let finish cooling.