My little dog should have his own West Jet account! I have taken him on many, many flights with me. Sherpa is by far the best brand of kennel to buy (although they are a tad pricey). Well made, comfy, mesh, extra pocket. My little dude likes to hang out in his even when we aren't travelling.
http://www.sherpapet.com/products
The medium used to fit under the West Jet seats, until they added life jackets under there, and now only the small will fit the max height allowance of 8.5inches. (When I flew Brandon to Calgary last time, it looked like there weren't any life jackets, and I wondered if a taller kennel would fit, but wouldn't want to try and get turned away at the gate!)
Your dog must be able to stand up and turn around in the kennel, and isn't allowed to come out or put his head out at any time. I always restrict my guy's fluids and don't feed him before the flight, to minimize the need for bathroom and the risk of vomiting. I wouldn't sedate a dog to fly, but if he was anxious, would try DAP spray (Dog Appeasing Phermone). Hope that helps!