no products, but training, training, training. And more training. Just get him used to being in his carrier and public transport before you fly. Assuming you live in Seattle, take him on metro rides as often as possible, starting NOW. Transpacific flights aren't exactly ideal for acquainting animals with public-transport travel...
Not-acclimated-to-travel, incessantly barking anxious dogs (or vocal cats...) are a real nuisance in airplane cabins. Something nobody wants and one of the reasons why more and more airlines impose ever-stricter limits on in-cabin travel.
Other than that, see that he's well tired-out from exercise and bowels are empty when it's time to get to the airport. As the flight leaves in the afternoon and you have to be at the airport by around noon, this should not be too great a disruption - just give him dinner early enough the night before so it'll have 'come out' before you start on your trip.
Ask your vet about possible medication, but use only as a last resort. The air in airplane cabins is thin (A350 is better than average in this regard) and there may be respiratory issues with sedated animals.