In a medium saucepan, bring water, milk, butter and sugar to a low boil over medium heat, stirring frequently. Cook for about 5 minutes at a simmer.
Remove from the heat and quickly stir in flour with a wooden spoon until completely incorporated and it forms a smooth ball. If it doesn't come together, place over low heat until it does, but stir constantly to avoid browning.
Transfer dough to the bowl of a stand mixer fitted with a paddle attachment or a large mixing bowl with an electric mixer. Beat until fluffy.
Add vanilla, mixing well.
Add eggs one at a time, beating after each addition and scraping down the sides of the bowl.
Preheat air fryer to 400 degrees.
Fit a pastry bag or large plastic bag with a #1M open star decorating tip. Add dough to the bag. You'll most likely need to add dough in batches.
Spray air fryer basket lightly with cooking spray.
Pipe dough directly into air fryer basket into 3-4 inch logs. Cut ends with scissors. Make sure to not crowd the fryer basket.
Lightly spray churros with cooking spray.
Cook for 6-8 minutes on 375 degrees or until golden brown.
Meanwhile, combine cinnamon and sugar mixture in a medium mixing bowl.
Remove churros from air frye and toss in cinnamon sugar mixture. Remove to a wire rack to cool.
Serve hot and fresh with your favorite dipping sauces.
If you've tried this recipe, come back and let us know how it was in the comments or ratings.
Please keep in mind that there are a lot of variables when making this recipe: water content in butter, milk, size of eggs and air fryer brand/type. If you need to make alterations to make sure the dough is correct, please leave those suggestions in the comments for other readers to use as they make their own!