You can't just replace a regular banana with a plantain, or vice versa. A number of important differences at a glance.
A banana is sweet and small. The plantain is starchy and firm and has a thicker shell. Due to the fixed structure, a plantain is suitable for baking. It is used as a vegetable in many countries. In short, the banana and plantain are not interchangeable in recipes.
This banana bread recipe is made with regular bananas.