Pat the wings dry, put them in a bowl, and season generously with salt and pepper on both sides. Leave them to rest for 10 minutes - the salt draws moisture out of the skin, which is what lets it crisp.
Pour the oil over the wings and turn them until every surface has a thin film on it.
Arrange the wings in the air fryer basket in a single layer with space between them. Cook in two batches rather than crowding the basket - wings that touch each other steam instead of crisping.
Cook at 200C (390F) for 15 to 20 minutes. Start checking at 15 minutes: the skin should be deep golden and look tight and dry, with the tips just starting to darken. Wing size and machine wattage vary, so judge by eye rather than by the clock. No need to flip them.
Tip the hot wings straight into a metal bowl, season with salt and pepper a second time, and toss. This second seasoning is the one you taste - do not skip it.
Serve immediately, while the skin is still tight and crisp.