Under 2026 TSA guidelines, a breast pump is classified as a "medically necessary" device, which grants it several important exemptions from standard carry-on rules. Crucially, most airlines do not count a breast pump toward your standard "one carry-on, one personal item" limit, meaning you can bring it in its own dedicated bag for free. You are also allowed to carry breast milk and cooling accessories (like gel packs or ice) through security in quantities exceeding the standard 3.4-ounce liquid limit, and you do not even need to have the baby with you to do so. At the security checkpoint, you should inform the officer that you are carrying a pump and milk; you may be asked to remove the pump from its carrying case for X-ray screening, similar to a laptop. While the milk may undergo additional screening (such as a vapor test), you have the right to request that it not be opened or X-rayed if you have safety concerns. It is a "pro" tip to carry a printed copy of the TSA policy to ensure a smooth interaction with agents who may be less familiar with the specific medical exemptions.