Preheat the air fryer: Set to 375°F (190°C) and let it warm up for 2–3 minutes. Lightly spray the basket with nonstick spray.
Scramble the eggs: Heat a small skillet over medium heat.
Add butter or oil. Whisk eggs with a pinch of salt and pepper, then cook, stirring gently, until just set. Remove from heat so they don’t overcook.
Prep fillings: If using peppers or onions, sauté them quickly in the same pan until slightly softened.
Stir in cooked bacon, sausage, or ham if using.
Assemble the quesadilla: Lay one tortilla on a plate. Sprinkle half the cheese over it. Add scrambled eggs, optional veggies/meat, and a drizzle of salsa or hot sauce if you like.
Top with the remaining cheese and the second tortilla. Press lightly.
Air fry: Carefully transfer the quesadilla to the air fryer basket. Cook for 3–4 minutes, then flip and cook another 2–3 minutes, until the tortilla is golden and crisp and the cheese is melted.
Rest and slice: Let it sit for 1 minute to set the cheese.
Slice into wedges. Serve with salsa, avocado, or sour cream.
Make it a grab-and-go: For a portable version, fold one tortilla in half with the fillings inside (a half-moon shape) and air fry 3–4 minutes per side.