As folks said, no problem with carryon frozen items with no freezer packs or ice. They usually open our well used Polar Bear 24 (sitting on the kitchen counter right now after a weekend trip) to check the contents. As long as everything is well frozen it will stay hard for a long trip.

I quit bringing the cooler for land-based trips on STJ. I did bring the cooler down four times in the last 12 months for sailing trips, since it shortens the provisioning trip so much to have the proteins pre-packed, marinated and seasoned, and ready to cook. But, I'm still tempted to bring down some growlers of fresh Mad Fox beer in my polar bear for the land based trips - works like a charm as checked luggage and the beer arrives cold.

Cheers, RickG