We purchased some of the Rum Runners cruise flasks. They are clear plastic pouches that are reusable, and come with a funnel to fill with liquids. After you fill them, you squeeze the air out of them so no bubbles are in the bag, and pack them in your check baggage. Suggestions are to put them between layers of clothing. They are undetectable by x-ray. Once onboard, and the luggage is delivered to your cabin, you open the valve on the pouch, and pour as needed into your glass. I'll let you know how they work out. We leave next Sunday the 26th of February.