Place the grated potatoes and grated onion in a large bowl. Using a clean kitchen towel, squeeze out as much excess moisture as possible from the potato and onion mixture.
In a small bowl, combine the ground flaxseed and water. Stir well and let sit for 5 minutes to thicken, creating a flax egg.
Add the flax egg, chickpea flour, salt, black pepper, and baking powder to the potato and onion mixture. Mix thoroughly until well combined.
Preheat the air fryer to 375°F (190°C) for 5 minutes.
Form the mixture into small patties, about 3 inches in diameter and 1/2 inch thick. You should get approximately 12 latkes.
Place the latkes in a single layer in the air fryer basket, making sure they do not overlap. You may need to cook in batches.
Air fry the latkes for 10 minutes, then carefully flip them and cook for an additional 8-10 minutes, or until golden brown and crispy.
Remove the latkes from the air fryer and let them cool slightly on a wire rack before serving.