Preheat air fryer to 380°F (193°C).
Wash green beans and pat thoroughly dry with paper towels to ensure crispness.
In a large bowl, toss green beans with olive oil, salt, and pepper.
Add dry aromatics based on variation: garlic powder (Way 1), thyme and zest (Way 2), red pepper flakes (Way 3), or onion powder (Way 4).
Transfer beans to the air fryer basket, spreading them into an even layer.
Cook for 8 to 10 minutes, shaking the basket vigorously halfway through the cooking cycle.
Remove beans when they are tender and edges are slightly charred.
Finish with wet ingredients: toss with Parmesan (Way 1), drizzle with soy sauce and sesame oil (Way 3), or drizzle with balsamic glaze (Way 4) immediately before serving.