I have checked whole cases in doubled manufacturers cardboard cartons- I squeeze the full carton into the next bigger size carton so the shell is two ply- never had any breakage from SFO to JFK. Of course now the weight of a full case domestically carries a charge. I also schlepped a case of Cape wines from South Africa to JFK padded with towels and clothes in an inexpensive suitcase I bought there for to handle all my acquisitions. No loss. And when I pointed out to the customs officer that I owe for a full case of wine, he blew it off- guess they can't be bothered if it's just a few bucks. I have heard Texas only allows 1 liter of alcoholic beverage per person. Anything more is confiscated. Don't re-enter the US via DFW or IAH after a wine tour of Europe if you're packing drinkable souvenirs!