TSA classifies peanut butter as a liquid.

The Transportation Security Administration (TSA) has classified peanut butter as a liquid, meaning it can only be brought in carry-on if it's 3.4oz or less. Creamy dips and spreads, hummus, and jam and jelly are also classified as liquids with the same requirements. Twitter users have expressed their displeasure with the rule. However, incidents of people trying to smuggle things in peanut butter through airport security have occurred in the past.