Preheat the air fryer to 375°F / 190°C for 3 minutes.
Brush the cut side of each bagel half lightly with olive oil.
Spread 1 tablespoon pizza sauce on each bagel half, then top with mozzarella cheese, pepperoni slices, and a pinch of Italian seasoning.
Place the bagel halves in a single layer in the air fryer basket.
Air fry at 375°F / 190°C for 6 to 8 minutes until the cheese is melted and bubbly and the edges are golden and crisp.
Let cool for 1 minute before serving to avoid burning your mouth on the hot cheese.