While I did not travel with any frozen items placed in my checked luggage I brought in it some cheese/ soft and hard variety. The items were still quite cold after 24 plus hours of travel inside small collapsible cooler bag with frozen gel packs. YMMV
It seems that dry ice is allowed in cabin and checked in luggage but could be an expensive proposition on UA;
TUESDAY, JULY 30, 2013
TSA Travel Tips Tuesday: Dry Ice
Questions about the transportation of dry ice generally fall into the hazmat realm where FAA has primary oversight. Since we often get dry ice questions, I felt that it would be a great topic for Travel Tips Tuesday.
My first tip is to check with your airline for any guidance they might have on traveling with dry ice. Dry ice is not prohibited by TSA. Secondly, as far as FAA regulations go, dry ice is permissible when traveling with perishables as long as you adhere to the following guidelines.
Packages of dry ice must allow for the release of carbon dioxide gas.
The limit for dry ice for both carry-on and checked baggage is five-pounds.
Packages of dry ice must contain the language "Carbon Dioxide Solid" or "Dry Ice" and must also have the net weight of the dry ice on the package.
https://www.united.com/web/en-US/con...e/fragile.aspx
Dry ice
United Airlines will accept packages containing 5.5 pounds (2.5 kg) or less of dry ice as carry-on baggage or checked baggage. The container or package must be ventilated to permit the release of carbon dioxide gas. The container or package must be marked as containing dry ice and must show the net weight and the identity of the perishable item. Styrofoam coolers containing dry ice will not be accepted.
For tickets purchased on or after September 4, 2014, dry ice is subject to a $150 USD* service charge (each way) per item for travel between the U.S., Canada, Puerto Rico and the U.S. Virgin Islands and a $200 USD* service charge for all other travel.
For tickets purchased between March 9, 2011, and September 3, 2014, a $100 USD* service charge applies to the transportation of dry ice as checked baggage on flights within or between the U.S., Canada, Puerto Rico and the U.S. Virgin Islands and a $200 USD* service charge applies to the transportation of dry ice as checked baggage on flights to all other destinations.
All fees referenced here are for one direction of travel only, and apply only when checking in with United.
Dry ice in quantities greater than 5.5 pounds (2.5 kg) will not be accepted.
Dry ice packaging used must allow the release of carbon dioxide gas, must be clearly marked as containing dry ice, and must show the net weight and identify the perishable item being preserved by the dry ice. Each container cannot have more than the maximum allotment per customer. Multiple customers cannot pool their portions together, even within the same traveling party.