Yes, you can fly with tuna packets in both your carry-on and checked luggage, but they are subject to the TSA's 3-1-1 liquid rule. While the tuna itself is a solid, the oil or water inside the packet is considered a liquid or gel. Most standard tuna packets are 2.5 to 3 ounces, which falls under the 3.4-ounce (100ml) limit, meaning you can keep them in your carry-on as long as they fit inside your single quart-sized clear bag. If you have larger "family size" packets or canned tuna, those must go in your checked luggage because they exceed the liquid limit and can appear "opaque" on X-ray scanners, often triggering additional screening. A major "pro-tip" for flying with tuna is to ensure the packets are not pressurized or crushed, as a leak in your bag would create a very unpleasant odor for the duration of your flight.