The classification of underarm deodorant by airport security depends entirely on its physical form. According to TSA and international aviation standards, solid stick deodorant is not considered a liquid and does not need to be placed in your clear quart-sized liquids bag; it can be any size and remain loose in your carry-on. However, gel, spray (aerosol), or liquid roll-on deodorants are strictly classified as liquids, gels, or aerosols. These must adhere to the "3-1-1" rule, meaning they must be in containers of 3.4 ounces (100ml) or less and fit inside a single clear, zip-top plastic bag. If you have a large 5-ounce spray can of deodorant, it will likely be confiscated at the security checkpoint. For 2026, many airports are installing advanced CT scanners that may allow you to keep liquids in your bag, but the volume restrictions of 100ml for non-solid items still apply globally to ensure safety and consistency across different security tiers. To avoid any hassle or potential loss of product, most frequent travelers prefer switching to solid sticks for their carry-on luggage.