In a large bowl or a stand mixer fitted with a dough hook, combine the flour and salt. Slowly add the warm water while mixing, then knead for a few minutes until the dough is smooth and not sticky.
Preheat the air fryer to 300°F. Divide the dough into 4 pieces. Roll one piece at a time on parchment paper to 1/4-inch thickness.
Cut out shapes with cookie cutters and re-roll the scraps. Use a straw or skewer to make a hanging hole in each ornament.
Arrange the ornaments in a single layer, not touching, in the basket or on parchment weighed down by the ornaments. Air fry for 30 minutes, flipping halfway, until completely hard. Add time in 5–10 minute increments if needed.
Repeat with the remaining dough. Cool the ornaments completely on a wire rack.
Paint with acrylic paint and let dry. Seal all sides with Mod Podge, letting each coat dry.
Thread ribbon through the holes to hang.
Notes
Salt dough is not edible and can be harmful to pets.
Air fryers vary. If ornaments puff or brown, lower the temperature to 200–250°F and increase the time.
Handprint ornaments (3/8 inch thick) need extra time.