Hey V., I would call the airline carrier and explain the situation and see what they suggest. I would get a doctor's note and have it with you to show as proof for his need of the supplement drink. Just make sure you keep the drink in the original container and depending on the size of the cans, I would keep it all together in a ziploc bag. If it's something you get from the pharmacy, you will need to have the prescription label on it for proof as a medical need. I had to call and get info for my husband when we travelled. He is a double amputee and with his sleeves over his stumps, he tends to sweat a bit so he has to take off his prosthetic and remove sleeve to air and dry out, but has to you use a type of lubricant to put the sleeve on. We had to get a letter from the doctor explaining why we have to carry the lubricant with us. The funny thing was, the type of lube that worked best for him was KY Jelly Silky lubricant. I picked on him about that, even though he was self conscious about that. Do not be surprised if they pull him over to the side to check him out because of the feeding tube. They pulled my husband over, even after I had warned them tha he would set off the alarms, and checked him out. He took his legs off voluntarily for proof, but other than that it was no big deal. Good luck.