Preheat a 6-quart air fryer to 400°F (205ºC) for 5 minutes. Meanwhile, in a large bowl, toss green beans with oil, salt, and pepper to evenly coat. Pour green beans into preheated air-fryer basket and cook until they begin to brown, about 5 minutes.
Remove basket from air fryer and shake to toss green beans. Return basket to air fryer and continue to cook until crisp-tender and charred in spots, about 2 more minutes. Transfer green beans to a serving platter or individual plates and serve.
