In a large bowl, combine the ground turkey, egg, breadcrumbs, red onion, 2 tablespoons of the salsa, chili powder, cumin, and salt. Add the cheddar and mix gently until evenly combined.
Shape the mixture into a compact loaf about 6 inches long and 3 inches wide. Line the air fryer basket with a piece of parchment paper cut to fit, then place the loaf on top. Spread the remaining salsa over the surface.
Air fry at 350°F for 25 to 30 minutes, until the center reaches 165°F on an instant-read thermometer. If the top browns too quickly, loosely cover it with foil for the remaining cooking time.
While the meatloaf cooks, make the salad. Combine the black beans, corn, red bell pepper, cilantro, lime juice, and olive oil in a bowl. Stir gently, then fold in the diced avocado.
Let the meatloaf rest for 5 minutes before slicing. Serve warm with the black bean corn salad alongside.