Preheat the air fryer to 400°F.
In a large bowl, toss the green beans with the olive oil, salt, and several grinds of pepper.
Working in batches if necessary, arrange the green beans in a single layer in the air fryer basket.
Air fry for 9 to 11 minutes, or until tender and browned in places.
Repeat as necessary with the remaining green beans.
Season to taste, squeeze with lemon juice, and serve.
