Preheat the oven to 350°F (180ºC). Line a 9-by-5-inch loaf pan with parchment paper.
In a large bowl, stir together zucchini, banana, sugar, oil, vanilla and egg.
In a medium bowl, whisk together flour, cinnamon, baking soda and salt.
Add flour mixture to zucchini mixture; stir well to combine.
Spoon batter into prepared pan.
Bake at 350°F (177°C) until a wooden pick inserted in the center comes out with a few moist crumbs clinging, 55–60 minutes.
Cool in pan for 10 minutes.
Remove bread from the pan and cool on a wire rack.
Serve warm or at room temperature.
