Aviation guidelines are vague, in order to keep security high. However, TSA guidelines state you can carry on more than the normal 3.4oz, as long as you declare it, at the discretion of the security team.
The TSA website states: “Formula, breast milk and juice for infants or toddlers are permitted to be brought on board the aircraft. As with other medically necessary liquids, travelers must tell the TSA officer at the beginning of the screening process that they wish to bring formula, breast milk and juice in excess of 3.4 ounces in their carry-on bag. These liquids are typically screened by X-ray, and formula, breast milk and juice in excess of 3.4 ounces will receive additional screening.”
To help you avoid any messes in the pool, ASDA Little Angels Swim range features nappies and pants which are super soft and secure, ensuring your baby enjoys a splash whilst giving you peace of mind in the water.