i have travelled with 3 days worth of milk, but not frozen. I had to be away from DS for my one and only business trip, so I pumped the whole time. What I did was buy a cooler with a strap that I could carry over my shoulder (at Target). It had enough room for all the bags plus a LOT of ice. I used the ice machine at the hotel to fill up big ziplock bags and put them under and over the milk. WHen i got home after about 10 hours of travel all the milk was still VERY cold and the ice had hardly melted.
Since yours is frozen already, you will want to keep it frozen or at least keep 4 days of it frozen since one day could be thawed and still good for that first 24 hours. I have read in several places (including Kellymom.com) that 24 hours is the max on thawed milk, but I admit I have pushed it to 36 and it has not had a negative affect on DS.
Can you get some sort of deep freeze cooler? I know people who have travelled with frozen food but that was pre 9-11.
Also, as for the airport - my experience was that the TSA were VERY understanding of carrying BM around with me and they quickly inspected it and let me be on my way. You can find their policies on the TSA website which says that BM is allowed to be carried through security onto a plane. Bring a copy of the policy if you are afraid of having issues.
Have a fun trip!
