Place the grated potatoes in a clean kitchen towel and squeeze out as much excess moisture as possible. Transfer to a large mixing bowl.
Add the grated onion to the bowl with the potatoes.
In a small bowl, combine the ground flaxseed and water. Stir well and let sit for 5 minutes to thicken into a flax egg.
Add the chickpea flour, flax egg, salt, black pepper, and baking powder to the potato and onion mixture. Stir until fully combined.
Preheat the air fryer to 375°F (190°C) for 5 minutes.
Form the mixture into 8 equal-sized patties, about 3 inches in diameter and 1/2 inch thick.
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 7-8 minutes, then carefully flip each latke and cook for an additional 7-8 minutes until golden brown and crispy.
Remove the latkes from the air fryer and let them cool slightly before serving.