Melt the butter in a microwave-safe bowl for about 30 seconds, or until melted.
In a large mixing bowl, add the cubed bread. Pour the melted butter over the bread, then add garlic, seasoning, and salt. Toss well until everything is evenly coated.
Place the croutons in a single layer in your air fryer basket. Work in batches if needed as this helps them cook evenly.
Air fry at 400°F for 3 minutes. Shake the basket to toss the croutons, then air fry for another 2–3 minutes. Keep an eye on them so they don’t over-crisp or burn.