Now that is impressive. The safety systems are all designed for humans and yet a dog in the backseat, who could probably not be properly secured, survived.
In the case of the car itself flying, and possibly tumbling on impact, I don't think the odds would be that good, as the dog would likely impact against hard surfaces. Or other passengers. That's maybe the least of the problems though, if the car's structural integrity is compromised...
I bought a new harness, with the largest contact area I could find, specifically for car usage.
http://www.sosubaru.com/dog-safety-harness.htm
Dog safety harnesses don't get anywhere near the scrutiny seat belts do.
...and yet I see those little dog test-dummies and I want to shove money through my screen despite the fact that I don't even own a dog.
Humans are silly...
Serious question. Smaller animals have less momentum and are more robust to a large deceleration.