Wash and dry the zucchini. Take each zucchini and cut via the hasselback method (not slicing all the way through), so zucchini is sliced but stays together.
Combine the olive oil, garlic powder, salt, and dried oregano in a bowl.
Place zucchini in air fryer. Brush top of zucchini with oil mixture.
Air fry for 5 minutes at 400 degrees F. Open the air fryer, and brush on the rest of the oil mixture. Air fry for an additional 10 minutes at 400 degrees F.
Plate. Sprinkle with red pepper flakes if desired.