I've jumpseated alot on Continental out of EWR, mainly to India. You cannot get listed for international jumpseats at the gate like normal. You need to find the employee travel office outside security. It's located just before security by the southernmost security checkpoint (I think its C1 checkpoint maybe) In terminal C. Go up to security and hang a left and there is a small office with a glass door. They can list you going and coming back. There are no taxes leaving the US, just taxes to get back in. Those you would pay in Canada on your return. After you get listed then you go to the gate and checkin like normal. Also, I believe you can sit in the jumpseat leaving the US, just not returning to the US. I know I've sat up front going to the Caribbean.

As for AA, I think the only regionals that can jumpseat international are Piedmont, PSA, and maybe Skywest. Might be one or two more, I'm not sure. Good luck!