I will probably be flying with all my boys by myself this summer.
Since Nadia is only 10 months, I don't have any advice as a parent, but when I was 10 we went to Hawaii on a family trip. My mom mad emy sister and I each a totebag and we got to select things to put in it to keep us busy, like books, puzzle books (I was really into word searches at the time), crayons, etc. Now I supposed you would include an MP3 player, gameboy, etc. It did help to keep us occupied, plus we had all we needed. I don't know how well this would work for your youngest, but it might be worth a try!
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We fly with my son every year...when he ws little it was hectic with all the stuff to bring..hahaha..and I only have one.