If you ship him underneath in cargo, don't forget there are temperature restrictions. Where would you transfer planes at? This summer has been hot in many cities! Please check the requirements for the airline you will be traveling on. There is usually a limit to the number of dogs allowed on board and in cargo. You will need to make a reservation for him at the time you make your own. There may be additional requirements since you are coming from Canada, you will need to check with the USDA, the CDC and the State of Massachusetts. You can find the requirements on the USDA website and it has links to each state.
http://www.aphis.usda.gov/animal_welfare/pet_travel/pet_travel.shtml
You need to make sure the carrier will fit under the seat so if the carrier you are considering is much larger than the large size Sherpa brand bag I doubt it will fit under the seat.
I used to travel with Arnie onboard about 10 years ago before 9/11. I trained him to get in and out of the Sherpa bag and to stay in for short periods of time. He almost always laid down in it. He never made noise even when we were in first class and they served food! Most people did not even know I had a dog. I also made sure I was comfortable carrying him in the bag. I figured if the airline employees thought I was struggling with him then he was too heavy and he would not be let on the plane. He was an older pup but weighed about 18-20 lbs.
Jennifer
