BA to AC on different tickets all business class.no baggage
 

I will be arriving around 7 pm from lhr on BA flight woth connection to Seattle on AC at 9 pm. With no checked baggage, can i go to TB facility for usa inspection without going to Canada immigration. I am us citizen. Thx

If you can get the DL BP to show. There will still be a cursory passport check.

actually it's ba to AC, still all business and no baggs

Same process/path. Only difference wrt airlines is whether checked bags are transferred or not which is not applicable to your case.

Assuming you're arriving in YYZ, no you can't. Your BA flight will arrive at terminal 3, while your AC flight departs from terminal 1. At present there is no way to connect airside, so you will have to go through customs to enter Canada, exit the terminal, take a short (free) train to terminal 1, then re-enter security. If you have Nexus (NOT Global Entry, it's not the same thing) then that will definitely expedite things for you.

A two hour connection is going to be tight, but barring flight delays you should be okay.

This is the YVR thread, so presumably not YYZ

D'oh.

Help needed on overnight connection at YVR.

My parents are going US to YVR to international, all AC. I'm travelling with them to YVR and then back to the US. I'm US citizen. My parents are not and they don't have Canadian visas. Arriving at YVR at around 8pm and departing at 11am the next morning.

It's too late for me to realize that we need to enter Canada to get to the Fairmont Hotel where I planned to stay overnight (correct me if I'm wrong).

My next option is to stay in the SkyTeam Lounge in the international departure area that I believe is open 24h, since I couldn't find any lounge in the US arrival area. I'd like to keep my parents company for the night. But for me to get there, I believe I'll need an international BP. I'm assuming that AC won't have a problem selling me a flight to an international destination when I already have one back to the US.

What I couldn't find out is, once I'm in the international departure area, can I go back to the US departure area? Thanks!

The Fairmont is landside so you would have to enter Canada to access it.

If you're travelling on AC you would not have access to the ST lounge. The MLL & Plaza Premium Lounge are not open 24 hours.

You will not be allowed to stay in the US arrivals area. You will need to proceed to Canadian customs and to the appropriate terminal for your connection. https://www.aircanada.com/ca/en/aco/.../us-int.html#/

AC will sell you another ticket, but they have a duplicate booking detector that is best described as inconsistent and unpredictable.

Thanks for the answers! I don't think I want to risk getting stuck in the international departures area (in the case AC didn't catch me checked in to two flights).
Fortunately, anyone can purchase lounge passes to access the ST lounge. I can't post a link here (since I'm a new user), but if you go to the YVR page for the ST lounge, down the bottom "How to visit the lounge".

I don't see anything at https://www.skyteam.com/en/lounges/vancouver/ about buying access

Let me try this, "www dot yvr dot ca slash en slash passengers slash shop-dine-and-services slash 505"

I would go by the Skyteam site, as that is more official than YVR.ca, the airport info site. They have no authority on who is admmitee.
If you are denied entry after getting to the international departure area, you will not be able to quote the airport website to fight your way in.

Despite living in Vancouver, I admit I am not an expert on connections at YVR but looking at the AC page, it seems you still have to go through Customs.
https://www.aircanada.com/us/en/aco/.../us-int.html#/

What passport do they hold and are you sure they can do this without a visa?

And yes, the Fairmont is landside. There are no airside hotels at YVR.

The ST Lounge does show up on Dragon Pass & Priority Pass so it appears to allow access via those programs. It does specify a 4 hour limit though which may or may not be enforced overnight.