Melt the butter in a saucepan over medium-high heat. Stir in the milk and salt, then reduce the heat to medium and bring to a boil, stirring constantly with a wooden spoon. Once boiling, quickly add the flour all at once and continue stirring until the dough comes together.

Remove the saucepan from the heat and allow the dough to cool for 5 to 7 minutes. After cooling, stir in the eggs one at a time with the wooden spoon until fully incorporated. Transfer the dough into a pastry bag fitted with a large star tip. Pipe the dough directly into the air fryer basket, making six even strips.

Air fry the churros at 340°F (175°C) for 5 minutes.

While the churros cook, mix the sugar and cinnamon together in a small bowl until well combined. Pour the mixture onto a shallow plate.

Once the churros are done, remove them from the air fryer and roll them in the cinnamon sugar to coat.