You can now buy special bags for trasnporting bottles. They are of thick plastic with triple sealing tops so, if the bottle breaks, nothing leaks. You then pack them in suitable clothing. There are more expensive bags with bubble-wrap built in. I used the type earlier this year and all was fine, including a transhipment at SIN. We also had some wine that was in the second type of bag, as supplied by the winery, they were also fine but not resuable.