It's common for US domestic flights to cross into Canadian or Mexican airspace. For example, a flight from Alaska to New York, Seattle to Boston, or Hawaii to Texas would likely cross into foreign airspace.

However, as far as I know, this is not legally considered a border crossing. In my experience, there is no passport control.

What exactly does the law say about this? What is the determining factor of a whether border crossing has occurred when air travel is involved? Can CBP check passenger IDs on domestic flights that crossed into foreign airspace?

Furthermore, if an domestic flight made an emergency landing in another country, what would happen to the passengers who don't have their documents with them? Is there a special legal provision for such scenarios?


1 Answer 1


On such a flight whilst it's overflying non-US airspace (not necessarily airspace over the U.S.A. proper, as the U.S.A controls airspace outside its own sovereign territory), then it is classed as being in the international airspace of the country that controls it e.g. Canada, or Mexico. As such, in the event of an emergency landing, then any passengers without suitable documents would most likely be returned to the country that they came from e.g. the USA.

Hopefully the authorities of that country e.g. the USA would then be able to let them back in, however this could get complicated because you aren't supposed to take luggage with you when evacuating an aircraft in an emergency. I honestly have no clue what the U.S. Authorities would do with someone who was returned to the U.S.A. from another country e.g. Canada, or Mexico, with no documents whatsoever in that scenario.

  • 1
    Unless you are a small child, you cannot get through airport security without presenting some form of valid ID, let alone bored the plane. The U.S. and Canada very likely have treaties covering this situation. Canada has gone so far as to grant passports to U.S. Citizens in violation of laws requiring they be issued to Canadian citizens only, but that was a more serious instant during the Iranian Hostage Crisis. Generally, the U.S. has gotten along fairly well with it's two neighbors in terms of border crossings.
    – hszmv
    Jan 11, 2021 at 13:47
  • Also, and I could be wrong, most domestic flights from Alaska to Continental U.S. will fly close the bound of territorial waters of Canada to avoid the issue slightly. A Hawaii to mainland U.S. generally land or take off from a major West Coast Airport. While there are no Passport controls in Hawaii, Hawaii does have very strict quarentine procedures for inbound animals and plants from the mainland. The U.S. isn't the only nation with this problem, as France has several "domestic flights" that must route over other nations and major oceans.
    – hszmv
    Jan 11, 2021 at 13:52
  • 2
    @hszmv in my experience US domestic flights do not avoid Canadian airspace. I've flown over southern Ontario many times on flights between the northeastern US and the northern western or midwestern states.
    – phoog
    Jan 24, 2021 at 15:31

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .