GREAT NEWS!
Your long airline flight will help a lot! Not well understood by many, is that commercial airlines, as they go up to altitude are NOT pressurized to sea level, but between 6-8,000 feet! Particularly if you manage to nap on the trip, you will be effectively acclimatizing!!
Drinking the fluids is a good thing, as long as it doesn't disturb your sleep! Skip the alcoholic drinks, though.
Good luck with the trip!
