🥜 Peanut Butter

TSA screeners will flag it at the X-ray because peanut butter is treated as a paste under the liquids rule. They will either ask you to surrender the jar or give you the option to check it if you have a checked bag. A jar under 100ml (3.4oz) is fine to keep and carry through.

TSA classifies peanut butter as a paste and applies the 100ml liquids rule to it, just like hummus or yogurt. Most other countries — including the UK, EU nations, Canada, and Australia — treat peanut butter as a solid food, so any size jar is allowed in carry-on there. If you are only flying domestically or departing a non-US airport, you can bring a full-size jar in your cabin bag.

Enforcement is consistent because peanut butter shows up clearly on X-ray as a dense paste. Screeners follow the same rule as any other gel or paste — over 100ml means it does not go through. There is very little room for discretion, so do not count on a screener letting a large jar slide.

Pack any jar larger than 100ml (3.4oz) in your checked baggage before you reach the airport — it cannot be resolved at the gate. If you want peanut butter in the cabin, buy a travel-size or single-serve packet, or pick up a small jar at an airside shop after security.