You have to exit Canada in order to land. If you are a US Citizen or permanent resident, you will need to have your passport stamped by the US side to demonstrate that you left Canada. Otherwise, you can tell the US side you wish to flag pole and they will refuse you entry (an "administrative refusal" that counts technically as a refusal but does not cause issues in the future.) In that case they stamp a piece of paper (the refusal) and that shows the Canadian side that you are entering Canada.
You have to exit Canada in order to land. If you are a US Citizen or permanent resident, you will need to have your passport stamped by the US side to demonstrate that you left Canada. Otherwise, you can tell the US side you wish to flag pole and they will refuse you entry (an "administrative refusal" that counts technically as a refusal but does not cause issues in the future.) In that case they stamp a piece of paper (the refusal) and that shows the Canadian side that you are entering Canada.
