Mix oats, flour, baking powder, cinnamon, and salt in a large bowl.
Whisk together mashed banana, milk, egg, melted butter, and vanilla in a separate bowl.
Combine wet and dry ingredients, stirring just until mixed.
Rest batter for 5 minutes.
Heat a lightly greased nonstick skillet over medium-low heat.
Scoop 2 tablespoons of batter per pancake onto the skillet.
Cook 2 to 3 minutes per side until golden and set.
Flip and cook 1 to 2 minutes more.
Repeat with remaining batter.
Cool slightly before serving to kids.