Will I be able to cross the land border into Canada with my Dutch?
The question that absolutely has to be answered is why is one flying out of Canada rather than the US? I can see entry being refused as there are flights available from the United States. Every application for admission will be evaluated on the merits. Where entry is permitted, Canada requires 14 day quarantine. A person traveling to a Canadian airport to catch a flight is going to come into contact with a lot of people, so I'm not sure this requirement would be waived in order to transit Canada. If so, then one would have to book two weeks hotel prior to departure and hole up, living on Skip the Dishes and room service for two weeks, not being able to leave their room except for medical emergencies. An alternative would be to fly to the Canadian airport and transit as an air passenger. Even better is just to fly from the US non-stop to Europe.