Preheat the air fryer to 375°F for at least 3 minutes while you mix the meatballs.
Combine ground beef, ground pork, panko, egg, lime zest, 1 tablespoon lime juice, chili powder, cumin, cayenne, kosher salt, black pepper, minced garlic, and chopped cilantro in a bowl; mix gently until just combined.
Portion mixture with a 1.5-tablespoon scoop and roll into 24 uniform meatballs; chill on a tray for 10 minutes to firm up.
Arrange meatballs in a single layer in the air-fryer basket, leaving ½ inch between each; brush lightly with olive oil if desired.
Cook at 375°F for 10–12 minutes, shaking the basket or turning meatballs halfway; they are done when internal temp reaches 160°F and exterior is lightly browned.
Whisk sour cream with ½ tablespoon lime juice and a pinch of salt for the lime crema; serve meatballs hot with crema and extra cilantro.