In 2026, TSA classifies breast milk, formula, and toddler drinks as "medically necessary liquids," meaning they are exempt from the standard 3.4-ounce rule. You can carry any "reasonable amount" in your carry-on, even if you are traveling without your baby. To pass through smoothly, you should inform the TSA agent at the start of the screening process and keep the milk in a separate bag or cooler for easier inspection. TSA may use specialized scanners to test the liquid; you have the right to request that they don't open the containers or that they wear fresh gloves. Accessories like frozen gel packs or ice are also permitted to keep the milk cold, even if they have partially melted. It's helpful to have the TSA guidelines pulled up on your phone or printed, and arriving 30 minutes earlier than usual is recommended to account for the additional screening time.