Prep the squash. With a sharp knife, trim the stem end for stability. Cut the squash lengthwise into two equal halves. Scoop out the seeds and stringy core with a spoon.
Season. Drizzle the cut sides with olive oil. Sprinkle with salt, pepper, and garlic powder. Rub the seasoning into the flesh so it’s evenly coated.
Preheat the air fryer to 380°F (193°C). Let it heat for about 3 minutes. A hot basket helps caramelize the edges.
Air fry, cut side down. Place the squash halves cut side down in the basket. If your air fryer is small, cook one half at a time. Air fry for 18 to 22 minutes depending on size.
Check for doneness. Flip the halves cut side up. The edges should be lightly browned and a fork should slide into the flesh with slight resistance. If still firm, cook 3 to 5 minutes more.
Fluff the strands. Using a fork, scrape the flesh from the edges toward the center to create long, spaghetti-like strands. Keep them inside the shell to form your “boats.”
Add sauce and toppings. Spoon marinara over each half (about 1/2 cup per boat). Mix lightly with the strands so the sauce reaches the bottom. Add any cooked proteins or veggies now.
Top with cheese. Sprinkle mozzarella and Parmesan evenly over the top. Add red pepper flakes if you like heat.
Back into the air fryer. Return the boats to the basket, cut side up. Air fry at 360°F (182°C) for 4 to 6 minutes, until the cheese is melted and bubbly with golden spots.
Finish and serve. Let the boats rest for 2 minutes so the strands set slightly. Garnish with fresh basil or parsley. Serve with a side salad or garlic bread if you want a fuller meal.