As of early 2026, the TSA has not banned peanut butter, but they have firmly classified it as a liquid rather than a solid food. This means that if you are carrying peanut butter in your carry-on luggage, it must adhere to the 3-1-1 liquids rule: it must be in a container of 3.4 ounces (100ml) or less, and that container must fit inside your single quart-sized, clear plastic zip-top bag. The TSA famously clarified this on social media, stating that since it has no definite shape and takes the shape of its container, it falls under the "liquids, aerosols, and gels" category. If you want to bring a larger jar of your favorite spread, you must pack it in your checked luggage, where there are no size restrictions. Solid snacks like peanuts or a pre-made peanut butter sandwich, however, are perfectly fine to bring through security in any quantity.