I have the same issue. What I do when I fly is to bring quart size ziplock bags. I fill one with ice to keep it cold on the way to the airport. I dump it right before we go thru TSA. As soon as we pass TSA I get ice from a food location inside the airport. They will fill the bag free when you tell them what its for. Once we are on the airplane the cabin crew will give you fresh ice to put in the ziplock bags as you need it to keep the insulin cold. I put the ice/insulin in a small insulated soft cooler to keep it cold. This will keep it cold without it actually getting frozen.