Originally Posted by
mxracer95
But "cabin air is fully replaced every two minutes."
Dry ice is allowed, but the quantity is limited so as the total onboard does not exceeds the aircraft's ability to manage the CO2. The problem comes when the dry ice is undeclared and not accounted for in the total of the dry ice onboard.
From
https://www.united.com/ual/en/us/fly...e/fragile.html
Dry ice
We’ll accept packages containing 5.5 pounds (2.5 kilograms) or less of dry ice as a carry-on bag or checked bag. Please make sure the container or package has proper ventilation to allow the release of carbon dioxide gas. You must also mark the container or package as containing dry ice, show its net weight and identify the perishable item inside. We won’t accept Styrofoam coolers containing dry ice.
For travel within the U.S. and between the U.S. and Canada, Puerto Rico and the U.S. Virgin Islands, we’ll charge $150 each way for each item. For all other travel, we’ll charge $200.
We won’t accept dry ice weighing more than 5.5 pounds (2.5 kilograms).
Multiple customers can’t pool their portions together, even if they’re traveling together.