Suppose you are flying over Canada en route from Seattle to?
If the plane makes an emergency landing, the passengers would remain onboard (unless the aircraft is on fire). They would not need passports as they would not be processed by the Canada Border Services Agency for the purposes of entering Canada. A similar situation arose in 2019 with a United Airlines flight from Newark to Hong Kong. It had to make an emergency landing in Labrador, and although those passengers obviously had passports, the decision was made to keep them on the plane for an excruciatingly long time, due to limited capacity to process large volumes of internationals at the facility. This led to a ghastly experience for everyone with lack of food, water and adequate toilets. Before some American starts banging on about those unreasonable Canadians a similar situation in reverse occurred a few years earlier. An Air Canada domestic flight from Toronto to Winnipeg had to divert to Grand Forks, North Dakota due to a runway issue at YWG. For safety reasons passengers normally cannot remain onboard a plane that is being refueled while its engines are operating, but the AC passengers had no choice because the Americans refused to allow them off. Customs & Border Protection had shut down for the day, and authorities would not even let the passengers deplane into the terminal while the aircraft refueled. Again, passports were not an issue because no one was permitted to leave the plane.