"We have to cancel our training for Wednesday. An unfortunate accident happened yesterday....Bailey jumped out of the window of our car in the neighborhood and broke his femur. We don't know what he was thinking. He is going to have surgery today for his hip and neutering and will have a 6 week recovery."
Didn't know what he was THINKING? He's a dog. He was thinking, "something smells really interesting over there and I'm gonna check it out" or "there's a dog ... I wonder if he wants to play" or a gazillion other possibilities. He had no clue jumping from a car could hurt him. He has people who are supposed to protect him from himself.
Do NOT let your dog hang body parts out of your car. Nor should you allow your dog to ride in the front seat. If you don't get that a dog distracting you while you are driving is not a great idea, think about this: a deployed airbag can seriously injure or kill your dog. Get your dog a harness that attaches to your seat belt system in the back of the car.