Not so simple
404:
Not that easy. If all your flights begin and end in a specific US port then Canadian company or not you are still in a very grey area.
As Apple says ALPA takes a very dim view of this.
The crew are currently operating on a CREW visa which allows foreign airlines/shipping co.s to change crew at an US out port, provided the crew do not domicile (er live) in the port/base/airport area.ie they are moved in to pick up the airplane/boat etc.
Still, could go badly.......