Preheat the oven to 350 degrees F (175 degrees C). Line 30 muffin cups with paper liners.

Mix flour, baking soda, and pumpkin pie spice together in a medium bowl.

Combine sugar and butter in a large bowl; beat with an electric mixer until smooth and creamy. Beat in eggs, one at a time, until fluffy. Add canned pumpkin, sour cream, and bananas; mix until well combined. Add flour mixture gradually, mixing until incorporated.

Fill the prepared muffin cups 2/3 full with batter.

Bake cupcakes in the preheated oven until a toothpick inserted into the center comes out clean, 15 to 18 minutes.