For older Model S/X, if you only need to carry a coat, it can often fit over the front seat headrest, draped over the back of the seat. If you have the parcel shelf, it can also be a great place to lay a jacket or dry-cleaning as the rear seats and hatch will prevent sliding around much. (May-2025 update)
For those who would like a traditional coat hook, one can be added, so long as you have a Panoramic roof.
J Hook
- EVhooks (Model S) EVhook (Model X)
Another good solution for a movable hook. It is available in black or silver.