Heat an air fryer to 400°F. Meanwhile, finely grate 1 ounce Parmesan cheese and place in a shallow bowl. Add 1 cup panko breadcrumbs, 1/2 teaspoon Italian seasoning, and 1/2 teaspoon garlic powder and mix to combine. Whisk 1 large egg and 1 tablespoon water toegether in a second shallow bowl.
Trim the stem from 1 medium eggplant. Cut the eggplant crosswise into 1-inch-thick rounds, then cut the rounds into 1-inch-wide fries. Sprinkle with 3/4 teaspoon kosher salt and toss to combine.
Working with one at a time, dip each piece of eggplant into the beaten egg and turn to coat. Dredge in the panko mixture, pressing to adhere, and place on a plate.
Lightly coat the air fryer basket with cooking spray. Working in batches if needed, place a single layer of fries in the basket (they can be touching but should not be stacked). Air fry for 8 minutes. Flip the fries and air fryer until lightly browned all over, about 7 minutes more. Serve immediately with marinara sauce for dipping.