Oh good grief. Just admit it was a boo-boo.
See, this is bullshit (link to ABC News). No dog wants to ride 7 hours at highway speeds. And, even if the dog did want to ride this way- no dog wants to have diarrhea, get hosed off at a gas station and go back up into the carrier on the roof.
Ann Romney's comment - "..the dog loved to go on vacation", is undoubtedly true. But, I think the pup would have liked it even more if he didn't ride on the roof - in a kennel full of dog poop. Like if he rode in the car!
And, of course, despite how much the dog loved it, this is illegal in Mass., New York, and Canada (states and countries they drove through).