Air travel with babies (kids) is never easy. When I used to travel for work, I would carry one small bag that fit into the overhead bin and call it a day. I had the TSA checkpoints down to a science, such as undoing my shoes and already getting my little toiletry baggies out before I even got to the conveyer belt for the x-ray machines. But baby has changed all of that. Now I'm that harried, haggard person standing there in line hoping that you all won't be mad at me as I rummage through the diaper bag to find all the food that I now need to declare, figure out what to do with my toddler who wants to toddle and not stay put, and then handle the stroller and the carseat expertly with one hand. Seriously, babies have a lot of gear and even traveling light, you can't avoid most of the stuff.
Here are some products I used on my most recent travels that made life a lot easier (note: I'm not sponsored by any of the products I'm mentioning and I don't get any commission etc if you click on the links, which lead to Amazon, btw).
* Enfamil Premium Infant Single-Serve Powder Packets: I usually pour pre-measured powder into bottles and then add water as needed, but one thing I found with travel is that with all the hectic running around, bottles aren't always dry when I need them to be. So now I use these pre-packaged packets where I can dump the powder into the bottle of water when needed and not worry about lugging around the giant tub of formula around. It also means that if a bottle is wet when I hit the road, no worries, since I'll be putting the powder in just before baby needs it.
I've really only used Enfamil so I have no idea if the competing brands like Gerber and Similac have such a product, but it's worth checking into. Also, these are pretty pricey compared to powder tubs (which are pricey to begin with!) but are worth it for the convenience.
There are also pre-made formulas out there in single servings, but I avoided them after hearing a horror story from one of the moms in my playgroup. Apparently, TSA needed to test the formula after they opened it, she had to dump it out and as a result, she had no food for the flight and had to go home. I do expect TSA to have to test powder (though on 6 flights so far -- 3 roundtrips), the most TSA has done is look at the tub of powder and wave a wand at it. However, even if they take a scoop of powder out for testing, the remaining is still good to use. So I'd avoid the pre-made formula, just to be safe.
* Medela Steam Bags: These bags are great for sterilization on the road. All you need is some water and a microwave and a lot of hotels now have microwaves in the room. I know sterilization isn't particularly necessary anymore but it's just something that I feel good about doing, especially when I know that the bottle cleaning might not be going as well as it might at home. And it's a decent value -- about $5 for 100 uses.
* Plum Organics Baby Food: I just used Plum Organics extensively (they were on sale at Babies R Us for a $1/pack -- usually run around $1.50 to $1.60 normal price), so hence my recommendation. There are other brands that come in a sack like this. The bottom line is that these are super easy to travel with since there is no worry about glass breaking and baby can easily suck the food out of the package so there's the added benefit of not needing to travel with silverware and dishes.
I packed enough food for the flight into a small generic cooler bag and purchased a bottle of water after passing through security. Incidentally, on one of my flights, I pre-filled the bottles with the appropriate amount of water and went through security and they let me through. I believe TSA allows you to bring as much food and water as required to feed the baby for the flight, but still be prepared to dump any water out or have TSA look/scan the food appropriately.
Once on the plane, I put the diaper bag up in the overhead bin and then put the cooler on the seat next to me. That way I had all of the food right there and I wouldn't have to bother my seatmate to get it. I also purchased a new toy for the flight but baby wasn't particularly interested in that or in any of my Kindle apps that I downloaded for her. She just wanted to pull magazines etc out of the seat pocket in front of us.
On my next trip, I plan to use the Travelmate and see how it works. Currently, I'm using a Graco Infant Carrier with the infant stroller frame (BTW, this stroller is awesome; I didn't know about it until after baby was born but it really is life-changing compared to the behemoth travel system stroller we purchased). We'll see how that goes!