Flying: Feeding Baby on Board
The good news is that breast milk is considered a "liquid exemption," which means you can bring more than 3 ounces on board as long as you are traveling with your child. (If your child isn't with you, the 3-ounce rule applies.) This also applies to formula or juice, canned baby food, and teethers filled with gel or liquid. If you're bringing these items on board, separate them from the cosmetics that you're carrying in your quart-size plastic bag. Declare you have breast milk (or formula, etc.) at the security checkpoint. To print out the official rules to have in hand, log on to tsa.gov/travelers/airtravel/children/formula.shtm.
Looking for a place to nurse in an airport? Find a quiet gate near your assigned one, or try one of those Internet booths. Some airports also have a kids' play area where you'll find a lot of understanding parents.