Every trip, I bring food in checked bags. I bring everything frozen in a box which fits inside a carrier/cooler like you would use for a casserole. My list is precooked bacon, cheese (not cream cheese), butter, sausage (like pepperoni), and brown and serve sausage. In the cooler I put a package of cream cheese and a couple of frozen bottles of water (triple wrapped). I wrap the whole thing in my bathrobe. (Yes, my bathrobe travels with me)
I usually bring a jar of peanut butter, english muffins, box of crackers and whole wheat wraps.
At disney, we buy eggs, creamer and OJ. And we are good for breakfast for the week with a few snacks to spare
We fly out of Phila. Usually the water bottles are slightly melted at the most. Once I wrapped an ice cube and the edges were still sharp. Didn't seem melted at all. Of course there is always the chance, bags get lost and all that, but so far so good.
Just to add we fly SW, so no bag fees. If I had to pay 25 -35 dollars for a bag that was mostly food, I might forget the whole idea and just buy stuff at disney.