I measured the back of my Model S, and it is around 38.5" x 72-75" (depending on where you measure, and how far forward the front seats are). This is about the size of a twin bed. So, I was wondering: has anyone tried to put a mattress (air mattress or otherwise) in the Model S? How does it work and feel? What are the best products? I am thinking that an air mattress with a 12V DC pump would work best. When I laid down in the back with the back seats down, it felt like it could be doable. However, if one's head is placed in the front, filling for the footwell right before the front seats is absolutely necessary. I read some posts about people putting full size mattresses in the Model S, but I think they were referring to deflated mattresses, not inflated/usable mattresses in the car itself. I do not see a way to fit a full size mattress in the car to be able to sleep on it.