Too bad sneaking in your doggie is impossible. Someone used to sneak their dog onto the plane. I think he would give it something to make it sleepy. But one day he got caught and they told him he either missed his flight or he did something with the dog. He had to give the dog away to someone at the airport. I could never run the risk of doing that. Although I wonder if flying from Mexico into the U.S. they wouldn't care to look at the dog's airline ticket, etc. But who knows what might happen at customs.
Too much to risk!