If you have a large (5.8-quart or larger) air fryer and two mini loaf pans you can make these cute little loaves of banana bread in under 30 minutes! For smaller air fryers, bake them individually or find a larger loaf pan that fits into the air fryer basket and pour all the batter into the one pan.
Combine flour, baking soda, and salt in a bowl (I use a stand mixer).
In a small bowl, mix the bananas, sugar, yogurt, vegetable oil and vanilla. Slowly combine the wet ingredients with the dry ingredients (I poured into the stand mixer bowl on low). Don't over mix, just combine well. Fold in the walnuts (if using).
Preheat the air fryer on 330°F for 3 minutes (optional).
While the air fryer is preheating, pour half the batter into one mini loaf pan and the other half into a second mini loaf pan. (No need to grease the pans if non-stick; if not non-stick, spritz the pans with vegetable oil.)
If you have a large (5.8-qt or larger) air fryer, Transfer the loaf pans to the air fryer basket; you may need to remove the basket and use a grill insert if the pans are touching the side). Air fry on 330°F for 20 to 22 minutes. (a toothpick should come out clean). If using a smaller air fryer, you will need to cook these separately or find a larger loaf pan that fits into the basket and pour all of the batter into the pan.