Cut your day-old bread into cubes and set aside. Using stale bread is ideal because it soaks up the custard mixture without falling apart.
In a large bowl, whisk together the milk, heavy cream, eggs, granulated sugar, brown sugar, vanilla extract, pumpkin pie spice, and a pinch of salt. Slowly fold in the pumpkin.
Add the bread cubes to the custard mixture. Mix thoroughly, ensuring that all the bread is coated. Allow the bread to soak for 10-15 minutes until it absorbs most of the custard.
Transfer the bread mixture to a baking dish that will fit inside your air fryer. If your air fryer is smaller, you may need to cook the bread pudding in batches.
Preheat your air fryer to 320 degrees F (160°C). Place the dish into the air fryer basket and cook for 20-25 minutes until the pudding is set and the top is golden brown. The cooking time may vary based on your air fryer model, so start checking around the 15-minute mark.
Let the bread pudding cool for a few minutes, then dust with powdered sugar and/or top with whipped cream if desired. Serve warm.