Do you want to know about fluid ounces in planes ? Here's the answer about how many fluid ounces can you take on a plane . The essentials like water, soda, and peanut butter should be placed separately from all the liquids, gels, and sprays like toothpaste, lotions, cough syrup, and others. Each passenger is allowed to bring one container of liquid that is no larger than 3.4 ounces or 100 mm. It is needed to pass through the security checkpoint individually with the quartz bag with the liquid products inside. The carry-on bag that passengers want to bring on the plane is primarily covered by this rule.