Can liquid ounces be authorized on a plane ? We all have questions about how many fl ounces can you take on a plane . There are several guidelines to follow when traveling with various liquid categories, especially hazardous liquids, whether you're flying either domestically or internationally. To get a better look inside a gift, officers might need to unwrap it. It is advised to ship gifts in advance or wrap them after the flight. Although drinks are typically not allowed through security checkpoints, once you have passed through security, you can buy food and drinks to bring on the plane.