Preheat the air fryer. Set it to 400°F (200°C) for 3–5 minutes.
A hot basket gives you better browning.
Prep the corn. Husk the corn and remove the silky threads. If your basket is small, break ears in half so they fit in a single layer.
Season lightly. Pat the corn dry. Brush with a thin layer of butter or olive oil and sprinkle with salt and pepper.
This helps crisp and season the kernels.
Air fry the corn. Arrange in a single layer and cook for 10–14 minutes, turning halfway. You’re aiming for tender corn with some charred spots. Thicker ears might need an extra 2–3 minutes.
Mix the sauce while the corn cooks. In a bowl, stir together mayonnaise, sour cream, lime juice (start with 1 tablespoon), grated garlic, 1 teaspoon chili powder, a pinch of smoked paprika, and a pinch of salt.
Taste and adjust lime and salt as needed.
Prep the toppings. Crumble cotija, chop cilantro, and cut extra lime wedges. Keep them ready to go.
Coat the corn. When the corn is done, let it cool for 1 minute so the sauce doesn’t slide off. Brush or spoon the sauce all over each ear, turning to coat.
Add the finishing touches. Sprinkle generously with cotija, more chili powder or Tajin, and cilantro.
Squeeze fresh lime over the top. For extra heat, dust with cayenne.
Serve right away. Street corn is best hot and messy. Hand out napkins and lime wedges.