Preheat the air fryer on Roast at 350°F and set the cooking time for 15 minutes if using a toaster oven—style air fryer or 12 minutes if using a basket-style air fryer. If using a toaster oven—style air fryer, line the cooking pan with parchment paper or aluminum foil.
Spread out the cabbage on the lined cooking pan or in the air frying basket. Sprinkle the bacon, onion, and salt evenly on top of the cabbage.
Roast the cabbage in the preheated air fryer. When the turn food notice comes on (or two-thirds of the way through the cooking time), give everything a stir to combine.
When the cooking program ends, transfer the cabbage to a serving dish and serve right away.