We will be leaving for vacation in a couple of weeks, taking our daughters Radian on board the plane with us for her to use during the flight. This is our first time flying with all three of us, my questions regard airport security checkpoint. Will the Radian fit in the X-Ray machine? Should we fold it down or leave it open? We will be using a cart to pull it behind us through the airport, I plan on removing it at security if I need to put it in the X-Ray machine. Also does the cart need to go through? It folds down small and from what I read that you are supposed to put strollers through the X-Ray machine, so I'm assuming it's the same for carts? Also, we could use some recommendations/suggestions on carry-on bags, there are two adults and one 2 year old on this trip. I cannot carry more than 35lbs and we will not have a stroller with us (we are borrowing one at destination). Right now we are thinking this for carry-on: 1 roller bag, 1 duffle bag, 1 backpack, 1 small folding cart for Radian. Also will the Radian fit on a small rolling cart through the plane aisles? Or will we need to take it off and carry it on board? We will be flying United Airline on a Canadair Regional Jet 700.