Preheat your air fryer: Set it to 390°F (200°C). If your model doesn’t preheat, add 2–3 minutes to the first batch.
Season the vegetables: In a large bowl, toss eggplant, zucchini, yellow squash, bell pepper, and onion with olive oil, oregano, thyme, red pepper flakes (if using), 1 teaspoon salt, and several grinds of black pepper.
Make sure each piece is lightly coated.
Air fry in batches: Spread a single layer of vegetables in the basket. Air fry for 10–12 minutes, shaking halfway, until edges are lightly browned and vegetables are tender-crisp. Repeat with remaining vegetables.
Avoid overcrowding so they roast, not steam.
Make the quick tomato base: While the last batch cooks, warm the crushed tomatoes and minced garlic in a small saucepan over medium heat for 5–7 minutes. Season with a pinch of salt and pepper. If you like, stir in balsamic vinegar or lemon at the end for brightness.
Combine and finish: Transfer all cooked vegetables to a large bowl.
Pour the warm tomato-garlic sauce over the top and toss gently to coat. Taste and adjust salt, pepper, and acidity as needed.
Serve: Top with chopped fresh basil or parsley. Enjoy as a side, or make it a meal with crusty bread, soft polenta, couscous, or pasta.