Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Crew members
Foreign members of crews working on foreign vehicles (for example, flight attendants and members of ships’ crews) do not need a work permit if the vehicle is in Canada for the international transportation of cargo or passengers.
link
http://www.cic.gc.ca/english/work/apply-who-nopermit.asp
I believe the US has the same exemption in the CFRs somewhere. Where the vehicle is registered is more important than where the flight begins.