Slice 1 loaf French bread in half lengthwise, then cut each half crosswise to create 4 equal pieces.
In a mixing bowl, combine 1/2 cup salted butter (softened), 2 teaspoons garlic powder, and 1/2 teaspoon dried oregano until well blended. Spread the butter mixture evenly over the cut sides of the bread. Sprinkle 1/4 cup grated Parmesan cheese evenly on top of the buttered surface.
Place the bread pieces, buttered-side up, in the preheated air fryer. Cook for 2 minutes, or until the tops are lightly browned.
Remove the bread from the air fryer and spread 1 1/2-2 cups pizza sauce evenly over the toasted surface. Top with 2 cups shredded mozzarella cheese and arrange 4 ounces pepperoni slices or other desired toppings on top.
Return the prepared bread pieces to the air fryer and cook for an additional 4 to 5 minutes, or until the cheese is melted, bubbly, and golden brown.
Let the pizzas cool for 2 to 3 minutes, then slice and serve.