Place the ground beef, breadcrumbs, egg, 1/4 cup teriyaki sauce, drained pineapple, green onions, garlic powder, salt, and pepper in a large bowl. Mix with your hands until evenly combined.
Divide the mixture into four equal portions and shape each into a small loaf about 3 inches long and 1 inch thick.
Preheat the air fryer to 375 degrees F. Place the mini meatloafs in the basket in a single layer, leaving space between them.
Cook for 12 minutes. Open the basket and brush the tops with the remaining 2 tablespoons of teriyaki sauce.
Cook for 3 to 5 more minutes until the internal temperature reaches 160 degrees F and the edges look crisp.