In a bowl, combine the flour, baking soda, salt, cinnamon and baking powder. Combine the egg, oil, sugar, banana and vanilla; mix well.
Add the banana mixture to the dry ingredients; stir just until moistened. Fold in pineapple and walnuts.
Pour into two greased and floured 5-3/4-inch x 3-inch x 2-inch loaf pans. Bake at 350 for 40-45 minutes or until a toothpick comes out clean. Cool for 5 minutes before removing from pans to wire racks.