Though using a loaf pan is recommended, if you don’t have one, either a baking dish or sheet pan will work. Just shape the uncooked meat mixture into an oval shaped loaf. Also make sure you let it rest for a few minutes after it comes out of the oven so it holds its shape while cooling. It will be less likely to fall apart. However, be aware that your meatloaf will be more susceptible to drying out or cooking unevenly if not cooked in a loaf pan.