Sometimes the hotel would freeze my ice packs for me other times I would use ice from a coffee place after I got through security. (lactationmatters.org)
One easy way to bypass this process is to check your breast milk in a small insulated cooler with frozen ice packs if you won't need it in flight. (babycenter.com)
When you're moving from place to place, the best way to store breast milk is in sealed containers kept in a small, insulated cooler with frozen ice packs. (babycenter.com)