oh, take the stroller. it doesnt sound like a big deal now but you will thank yourself once your in the airport. i dont want to sound like a "debbie-downer" but these days you never know how long your lay over might actualy be.we flew thru atlanta a few months back. what went from a 45 min.lay over, turned into a 8 hr one. i was so glad that i didnt have to lug my 2 kids around atlanta airport that whole time, plus its a great luggage cart for everything else. you just check it at the gate. no problem at all. oh,about the carseat, i just put the it on top of the stroller umbrella shade. its worked for me. i travel alot with my kids,i mean alot. i am always glad to have it. just my advice... i hope you have a wonderful trip full of beautiful memories with your 2 kids and family. safe travels