In a large bowl, mix together the milk/vinegar mixture and the okra. In another large bowl, combine the cornmeal, flour, and seasonings. Toss the okra by the handful in the cornmeal mixture, and transfer it to a lined baking sheet in a single layer. Put the okra into the freezer for 15 minutes.
Transfer the okra from the baking sheet to your air fryer basket, until you've filled the bottom with a single layer. It's okay if they are touching some, but you don't want a ton of overlap. Spray the okra lightly with the spray oil, and air fry for 8-12 minutes at 400° F, stopping every 4 minutes to shake the basket and spritz any parts of the okra that look dry with the spray oil. Your okra is cooked when it's golden brown.
Repeat with the remaining okra, until it's all cooked. You can keep the cooked okra warm on a cookie sheet in the oven at 200° F while you cook the rest of the batches. It will take 2-3 batches, depending on the size of your air fryer.
Video
Notes
The cooking time assumes that you did two batches.About the milk/vinegar mixture: We're basically making vegan buttermilk here. Buttermilk's acidity (in this case from the vinegar) helps the cornmeal coating stick better and helps the okra brown better. I recommend mixing up the "buttermilk" first, then doing the rest of your prep, so the milk has a chance to curdle a bit. Curdling isn't often the goal in cooking, but today it is!About the spray oil: It's very important that you use non-aerosol spray oil in this recipe, because you will be spraying the okra while it's in the air fryer basket. Aerosol oil sprayers can damage your basket's nonstick. Invest in a spray bottle like this one.About the cooking time in step 2: I know that 8-12 minutes is a big range, but it really depends on the size of your okra and your air fryer. The second batch will also cook more quickly, because the air fryer will be hot from the jump with that batch. Just check in often during those last 4 minutes. Your okra is cooked when it's golden brown.