L.K.
If she 's still in diapers don't forget Huggies overnites.Also, a change of clothes for her just in case. I changed my twins right before boarding and on the plane on the seat , the bathroom is too small.I put all the snacks in separate ziploc bags to keep my bag organized.You may want to buy her a little wheeled bag. My mom got one at walgreens that was a frog or a dog. They pulled them around the airport and it kept them busy.And fill it with crayons , coloring books,doodle pro,stickers,a couple of new books,snacks,etc. i wouldn't let her out of her seat unless you are changing her or you won't be able to get her back in:)Good luck and have fun!