Bring as much as you’ll need for the flight. Baby food, formula, and milk are exempted from the 3-ounce rule for liquids, but you do need to declare it at security so it can be inspected separately. They run a harmless test on excepted baby liquids, and once they’re done they will reseal it and give it back to you.
Even for parents traveling with children, water is still not allowed, so plan to buy it or bring a reusable filtered water bottle to fill up once you’ve passed through security.