Place green beans in a bowl and add olive oil (I use 2 tablespoons, but if you'd like to use less, just make sure you have enough to have them coated.)
Sprinkle with salt and pepper and toss to coat.
Place in air fryer and spread beans out into an even layer.
All air fryers are different, but I suggest cooking for 6-8 minutes for soft green beans that get browned and slightly crisp on the outside, and 8-10 for a crisper bite. Give them a shake about half way through cooking and that's a good time to check.
Notes
These beans are best made fresh! If you have leftovers, store them in an airtight container in the fridge and consume within 2-3 days for best results.
Feel free to experiment with adding other seasonings like seasoning salt, onion, or garlic.