Yeah, my retriever used to jump out even when the window was only like 4 or 5 inches. And she isn't exactly a small dog. My labs do it like crazy though so I have to leave the car on and the AC going when they take rides. They've never tried to jump out when the car was moving, though.

Our black lab USED to do that. We have the suburban and would leave her in the back with the windows down (for air) while running errands and she would jump out. She attempted to jump out while at a stop sign once - that got me nervous so I took to leashing her and using the seat belt to hold the leash. About a week later she jumped out when we went into the store - the leash was not long enough for her to put all fours on the ground - luckily that was a short stop and I was their almost immediately. There she was scratching away at the door with her front legs trying to get back in hung up by her collar - her back legs doing their darnedest to get enough of a boost to jump back in. Its kind of funny now - at the time I was pretty scared and upset thinking she could have hung herself to death. I shortened the leash - a lot after that. However she did learn her lesson - she never has attempted to jump out of a window leash or not ever since. Today she rides in the back of the 'burb with her head hanging out the window. She does know how to roll down the windows - not just the electric ones in the back of the car, she also can work the hand crank of the suburban she learned that on the old mustang we had. lol She also learned how to open the door from the inside by pawing at the handle just so.

No, but I have a dog who keeps jumping through my screened in back porch.