In a large bowl combine the ground beef, finely minced celery, grated onion, panko bread crumbs, Greek yogurt, Worcestershire sauce, garlic powder, Italian seasoning, beef bouillon, salt and pepper, and one egg. Use your hands to mix it all together.
Form the mixture into either one large loaf or two equal loaves.
While preheating the air fryer, mix up the ingredients for the glaze in a small bowl and set aside.
Place loaf or loaves into pre heated air fryer. Cook at 380F for 35 minutes. Check with a meat thermometer around the 25 minute mark. If the tops are browning too quickly you can cover with tin foil and continue cooking. Once the meatloaf reaches 155F you can remove the tin foil if using, and brush a thick coat of the glaze on.
Cook for another 5-10 minutes at 380F to caramelize the glaze and make sure the internal temperature reaches 165F.
Slice and serve. Enjoy. Leftover glaze can be used for dipping.