I've traveled several times with a breast pump and with milk and have had some minor problems, though all where ultimately resolved. My suggestions:
--Leave extra time. If you run into questions at security, having extra time makes the whole situation less stressful.
--Some airports have a "Family/Medical" line in security. If the airport does, use this line! The inspectors in these lines are usually more aware of the regulations regarding breast milk. In addition, most--if not all--of the passengers in this line are either traveling with small children, traveling with family members who some reason travel more slowly, are traveling with breast milk or formula, are traveling with medicines or medical equipment, etc., so I find they tend to be patient and understanding and don't rush if it takes you a moment to separate your items or if you're answering questions.
--If you have more than 3 ounces of breast milk, be sure to separate it from any other liquids and declare it.
--You're not required to declare a breast pump, but I recommend doing so. I didn't declare it once and it was mistaken for an explosive device on the x-ray. Everything worked out fine, but there was a bit of commotion for a few minutes and they did have to remove it for additional testing.
--Since you need to remove the breast milk and the inspector may ask to see the pump, try to pack so those items are easy to, if needed, take out and put back away.
--Print copies of the TSA regulations (
http://www.tsa.gov/travelers/airtrav...n/formula.shtm and
http://www.tsa.gov/travelers/airtrav...eds/index.shtm) for each time you need to go through security. You don't need to have this, but if you run into an inspector that's not as familiar with the TSA regulations regarding breast milk or ice packs, it's helpful to be able to hand the printout to them. Each time I've run into a problem, politely handing these to the inspector resolved things.
--Politely ask for the supervisor if there are questions or concerns. I've only had to do this once (when I had an inspector who said that the exception about breast milk applied only if I had my baby with me); the supervisor was quick to come over and handled the situation very professionally.
And one more, unrelated to security, put an extra plastic bag around each container of milk. In case the container or bag that the milk is in leaks, if it's in another bag, you don't lose any milk! :-)
Have a good trip!