Start by making the mix, in a large mixing bowl mix together the flour, baking soda, salt, egg, and sugar.
Then mix in the oil, milk, and vanilla. Mix well.
Add the bananas.
Mix until smooth. If using walnuts, stir the walnuts in now.
Pour the prepared batter into a prepared air fryer safe pan, that has been coated with non-stick cooking spray.
Set the temperature for 310 F, and the time for 30 minutes. After 30 minutes check and check for doneness. If it is not done, add another 5 minutes. Until it’s fully cooked, and a toothpick comes out clean.
Once fully cooked, remove the loaf pan, from the air fryer basket, let cool slightly.