Ok, I don't have a baby any more so I won't have to worry about this fortunately (ds never had a diaper rash problem thankfully anyway). I was doing some reading on another travel board and thought I would pass on some information I read there about what's allowed, not allowed, etc:
1. Obviously, no liquids, gels or creams of any sort, which include diaper cream, unfortunately. But since my son is on antibiotics, he gets a horrible diaper rash and is prescribed a certain kind of diaper cream, which is allowed on as long as I have his birth certificate with me to match the prescription. Prescriptions are allowed as long as they are in the original package with the prescription sticker.
2. They will allow the pre-made formula that you purchase in the store or powder formula. I just read a recent article that says you will not have to taste the formula. Here is the link to the article:
http://travel.msn.com/Guides/article.aspx?cp-documentid=347544>1=8489
3. Solids are allowed, food and snacks as long as they aren't in liquid form. If the baby food you have is in it's original package and not opened, they'll accept it. First stage baby foods are very liquidy and I wouldn't put it passed the TSA to confiscate it if it was open. From what I've heard, they've been extremely strict.
4. And you've all probably heard that certain makeup, lotion and shampoos are not allowed either. What sucks is that the air is so dry up there that I need lip balm and they won't allow that on as well.
One idea that came up (and I DON'T KNOW if this would be breaking the rules or not so use this tip at your own peril) was to put a smear of diaper cream in the clean diapers you're taking with you. Not sure if that's breaking the rules or not but it's sure creative!
hth!
ETA: obviously I copied and pasted someone elses post but that at least will give you an idea of what this person found out in a similar situation... hth.