Preheat the air fryer to 400°F. Place the frozen green beans in a bowl and drizzle with olive oil. Sprinkle with salt, pepper, onion powder, and garlic powder. Toss to coat.
Place the vegetables in an even layer in the air fryer basket. Air fry for 5 minutes. Shake the basket and air fry the green beans for 5-6 more minutes. Adjust seasoning to taste. Serve topped with butter, if desired.