DIAGNOSIS You're asking if you can bypass the main cooking container. The short answer is no, you shouldn't. The basket (or the provided tray/rack combo) is a critical part of the air flow system.
FIX Always use one of the official cooking inserts: the perforated basket, the solid crisping tray, or the dehydrating racks. These are designed to sit at the correct height above the heating element and allow hot air to circulate underneath and around the food. Using a random pan or dish will block airflow, cause uneven cooking, and likely trigger overheating errors.
IF THAT DIDN'T WORK If you need a different vessel for a specific recipe (like a cake pan), it must be oven-safe and shallow enough that there's at least an inch of clearance between the top of the pan and the heating element when the door is closed. You still must place this pan on top of the provided wire rack, not directly on the element.
HEADS UP Placing anything directly on the floor of the oven (where the heating element is) is a major fire risk. It will also instantly ruin the non-stick coating on that surface and probably melt anything not rated for very high direct heat.