Preheat the air fryer to 375°F (190°C).
Prepare a breading station: place whisked egg whites in one shallow bowl and combine panko, Parmesan, oregano, garlic, salt, and pepper in a second bowl.
Dredge each eggplant slice in the egg whites, allowing excess to drip off, then press firmly into the seasoned breadcrumb mixture to ensure total surface coverage.
Arrange the breaded eggplant in a single layer within the air fryer basket, ensuring no overlap to maintain optimal airflow.
Cook for 10 minutes, utilizing tongs to flip the slices at the 5-minute mark for even dehydration and browning.
Apply approximately 1.5 tablespoons of marinara sauce to the top of each slice and distribute the mozzarella cheese evenly over the sauce.
Execute a final cook cycle for 2 to 3 minutes until the cheese reaches a molten state and shows slight browning.
Remove from the air fryer and allow to rest for 2 minutes to stabilize the structure before serving.