Hello everyone...Tomorrow I will be flying from Macau to Incheon Airport via Air Macau. A few hours after arriving, I will then catch a Delta flight from Incheon to NY (with a layover in Seattle). Is there a way I can arrange for my bags to be checked straight through instead of having to pass through Korean immigration to get the bags and then reenter through security again? Thanks in advance!

You should first check to see if they have an interline agreement (my guess is that they do).

If so, inquire with air Macau and see if they are currently honoring in on their end.

According to Expertflyer Air Macau (NX) does not have an interline agreement with Delta and cannot check luggage through to DL. You will have to collect your bags and check them in with DL.

Thanks for the input...I was able to get my bags checked through to Seattle though I will have to collect my bags and pass through customs in Seattle and then re-enter security for my flight to NY. Not the best scenario but much better than having to go through Korean customs just for my bags.

Um. That's a US law.

You would always have had to do this.

Edited to remove a bunch of information deemed non-relevant after I reread the original post.

As posted, this is standard - not only in the U.S. but in other countries I'm familiar with as well. Airports that handle international arrivals are equipped and staffed for immigration and customs. The hundreds of small airports to which one might continue one's journey are often not designed, equipped or staffed for this purpose. It would be impractical to redesign baggage handling to keep bags that arrive internationally segregated until their owner claims them at his or her final destination - which would then need customs staff to handle one or two international arriving passengers per week. And bags are just one part of the overall process.

You can generally re-check bags to their final destination directly outside customs, without having to go to the regular check-in area.

With connecting flights in Europe, for example, you'd never see your bags until final destination, though you need to enter Schengen in the first arrival country.