Preheat an air fryer to 370 degrees F (190 degrees C). Separate out 1/2 cup corn and set aside; pour remaining corn into the bowl of a food processor. Add flour, egg, sour cream, and mayonnaise. Pulse until mixture is incorporated.
Pour contents of the food processor into a mixing bowl. Add reserved 1/2 cup corn, onion, cheese, cilantro, lime juice, chili powder, salt, and granulated garlic. Mix well.
Place a perforated parchment liner into the air fryer. Using a scoop, place 2-tablespoon dollops of fritter mixture into the basket. Air-fry fritters for 12 minutes, flipping at the halfway mark. Sauce:
Mix sour cream and lime juice together. Drizzle over cooked Mexican street corn fritters.