Korean Air Skypass - KE 61 / 62

Booking ticket from Asia to San Paulo on KE website. I understand that there will be a technical stop at LAX. A dialog box said traveler needs to provide "relevant document for U.S. immigration."

Do people need to clear customs at LAX for this flight's technical stop?

Yes. It's not just a technical stop, not like the old days at Anchorage. It's a real stop. Everyone must get off the plane and clear US Customs and Immigration.

I'm 99% sure on this, but haven't taken the flight myself, so someone else might verify.

Ok. Thanks for the info!

Technical difference here, but most people go through Immigration but not customs. After immigration, you are taken to a transit lounge. Some nationalities need a US transit visa (but not typical entry visa).

I usually go through customs as the VIP area of the transit lounge is terrible. However, going though customs will often attract a bit of attention from customs officers wondering why you don't have any luggage with you. Every other time it seems I get questioned on it and it takes a few minutes to explain to them that "no I don't have to get my luggage yet" and "yes I've done it before". Don't try this if you have any duty free that won't make it through security as a carry on.