The human body can survive tremedous deceleration, if the forces are spread over your whole back. Supppose we designed cars where the driver and passengers face the rear 9you would steer with the help of a forward-looking TV camera.
In a frontal collision, the seatbacks would absorb the force. plus, no real need for seatbelts.
Would this work?
I would think that driving while your kinesthetic sense tells you you are going the opposite way that your eyes tell you will cause more than enough accidents to outweigh the admitted safety benefits of the rearward facing position. You could put just the drivers seat facing forward, and help the passengers with no driver retraining required.
Planes would benefit from this as well, but passengers hated that seating arrangement so they got rid of them. The complexity and confusion of having a driver face the wrong way would kill this idea anyways.
There are already too many people who can’t drive facing forward. This is a really, really, really dumb idea.
Southwest Airlines had some rear facing seats several time when I flew with them. I liked them - felt a little different and different is good.
While I don’t really worry about being in an accident when on an airliner, I did also enjoy the thought of the extra protection.
As for cars, it would be a good design for the car that DOES the rear ending, but not the target. 
Would you really have that much more protection in an airplane crash? (I’m talking a fall-out-of-the-sky crash, not one of those still-on-the-runway crashes that people sometimes survive.)
Nothing will help you in the “fall-out-of-the-sky” scenario.
However, most airplane accidents take place during takeoff and landing, which I suppose fall into the “still-on-the-runway” scenario. Most of the time people do survive them. So I’m guessing there might be more protection with rear facing seats.
I’d be interested to hear from an engineering type on that before I get too excited about it though. I’m just a dumb pilot type.
As said, if you hit a mountain at 600 MPH, a backwards facing seat, seat belt, or upright tray table will not do you much good. But in a rough landing, collapsed landing gear, taxi collision, or other ground accident, the rear facing seats will indeed offer more protection.
There are some smaller planes (Fokkers, IIRC) that have the first row facing backwards. I flew in those seats from Aspen to Denver once, and it’s really interesting looking at a whole planeload of people when taking off and landing.