Preheat oven to 325°. In 2-quart mixing bowl, mix: flour, salt, baking soda and baking powder. Set aside. In 4 quart mixing bowl, blend butter and sugar with electric mixer until creamy. Add eggs and blend until fully combined. Add bananas and blend until fully combined. Gradually add dry ingredients to butter and sugar mixture. Blend until fully combined. Pour batter into greased, 9 by 5-inch loaf pan. Bake for 60–75 minutes, until a toothpick inserted into the center comes out clean. Cool bread in pan for 10 minutes. Loosen sides of loaves from pan with a butter knife. Turn pan upside down onto cooling rack. Tap bottom of pan with backside of butter knife until loaf releases from pan. Remove pan, turn bread over and let cool for at least 30 minutes before slicing. Wrap completely cooled bread tightly in plastic wrap or plastic storage bag. Store for up to 4 days at room temperature or 7 days in refrigerator.