Cut the bread into 1-inch cubes. If the bread is very fresh, let the cubes sit out for 15–20 minutes to dry slightly.
In a medium bowl, whisk together the eggs, milk, sugar, vanilla, cinnamon, and salt until smooth and fully combined.
Add the bread cubes to the bowl and gently toss until evenly coated. Let them soak for 1–2 minutes — no longer, or the bites will turn soggy.
Preheat the air fryer to 370°F (188°C) for 3–5 minutes. Lightly spray the basket with cooking spray.
Arrange the coated bread cubes in a single layer in the basket, leaving space between them. Work in batches if needed.
Air fry at 370°F for 8–10 minutes, shaking the basket halfway through, until the French toast bites are golden brown and crispy.
Serve immediately with maple syrup, powdered sugar, whipped cream, or your favorite dipping sauce.