Preheat oven to 350°F and grease a 9x5-inch loaf pan.Whisk flour, baking soda, baking powder, cinnamon, and salt in a bowl.In another bowl, whisk sugar, eggs, oil, and vanilla until smooth.Stir dry ingredients into wet ingredients until just combined.Gently fold in diced apples.Pour batter into pan and smooth the top.Bake for 55 to 65 minutes until a toothpick comes out with moist crumbs.Cool slightly before slicing and serving.