Yes, Vaseline (petroleum jelly) is considered a liquid/gel by the TSA and most international aviation security agencies. Under the 3-1-1 rule, any substance that is "spreadable, smearable, or pourable" is classified alongside liquids. This means that if you are carrying a standard tub of Vaseline in your carry-on, it must be 3.4 ounces (100ml) or less and placed inside your single, quart-sized clear plastic bag. Many travelers are surprised by this, as they view Vaseline as a solid; however, security scanners flag its density as a gel. If you have a large 13-ounce "family size" jar, it must go in your checked luggage, or it will be confiscated at the checkpoint. A helpful travel tip is to purchase the miniature "lip therapy" tins or tubes, which are specifically designed to be travel-friendly and easily clear the 3-1-1 requirements without taking up much space.