I'm taking a trip to PA next week with my two boys, 4.5 & 2.5. I am going alone and am 7 1/2 mo pregnant. My 2.5 is pretty wild and I know if he is only in the the airplane seat, it will be a miserable flight. Not to mention, it's not as safe or comfortable. I don't know what the CARES system is, but I plan on taking his carseat. I am going to use one of those metal luggage wheel systems to pull it through the airport. Then I can also double it as a stroller (as long as I feel I can secure it tightly). Then on the plane, he knows when he's in his car seat, he's stuck there just like a car. This will also be much more comfortable for a nap. His seat is the Sunshine Kids Radian (made of steal) and weighs almost 20 lbs, but I'm going to deal with it. I also don't trust checking car seats. The airplane workers don't care if they throw it around or drop it. How would that be different than getting into a slow/low impact accident? My 4.5 uses the same seat and I'm trying to decide if I want to try to carry his as well onto the plane or borrow a booster seat from a relative at destination. Bottom line, you are traveling with one child, you CAN do it if you want to. The gate person and attendees will assist you if you need help.