For Grilling:
Prepare a grill for medium-high heat; heat 5 minutes (or preheat a grill pan over medium-high heat).
Grill corn, turning often, until slightly charred all over, about 10 minutes.
Meanwhile, in a small bowl, mix mayonnaise and crema.
Transfer corn to a platter. Brush with mayonnaise mixture. Top with cotija, chili powder, and cilantro. Serve warm or at room temperature with lime wedges alongside.
For Air Fryer:
Cut corn to fit in air-fryer basket (you may need to cut cobs in half).
Brush corn all over with oil. Working in batches, arrange corn in basket and cook at 400°, turning halfway through, until tender, 10 to 12 minutes
Meanwhile, in a small bowl, mix mayonnaise and creama.
Transfer corn to a platter. Brush with mayonnaise mixture. Top with cotija, chili powder, and cilantro. Serve warm or at room temperature with lime wedges alongside.