I’d like to know a bit more about the cost involved and who will end up paying for all this. I can imagine this to be a financial and logistical challenge at Taoyuan International Airport where there are currently two very old Terminals, one from which China Airlines and their SkyTeam partners such as Delta operate. Then another one for EVA Air and Star Alliance.
Both terminals are definitely coming into their years but not only that, having a pre-clearance facility there means that all airlines should use it in order to make it worthwhile.
This means the airport needs to designate one part of the terminal (or build a new one) for U.S. departures which is sealed off past the U.S. Immigration checkpoint.
One advantage of doing pre-clearance is that aircraft can go from Taiwan directly to other airports, bypassing overloaded airports like LAX. In a post-COVID world, they can also avoid having people arrive sick. The Asian countries have done much better with Covid, and keeping them separate would be a win.
There is probably also more customs pre-clearance of freight going on, and a lot of air freight goes via passenger aircraft.
All Canadian international airports are set up this way, and frankly it sucks. The worst part is you need to budget quite a lot of extra travel time before your flight since you need to clear customs before boarding the plane. Less terrible but still annoying, since there's a separate terminal just for US departures, if your party is going to different (US & non-US destinations) you have to split up.
It’s basically built for Nexus cardholders.
But awfully nice to land as a domestic flight. Would rather deal with CBP officers in Toronto than those based at US airports constantly on high-alert because they deal with people from ???.
You just go through immigration/customs in Canada (it looks very similar to those in the US). Then once you land they treat it like a domestic flight - so it allows airlines to fly to more airports (not all US airports have customs) and relieve some congestion at customs itself.
One annoying side effect of this is that you can’t bring most foods onto the gate/flight because you’re technically in the US now. But it’s somehow ok to have local fast food places inside the terminal.
Also, this seems like a good way to get to Phoenix on time.
Other than that, this is probably a good thing in terms of increasing customer choice. If someone doesn't want to deal with this, they can still fly via an intermediary point.