Myself, my dh, and our 2 girls each carry a backpack as our carry on. We all have our own personal items such as 1 outfit, nessasary items like glasses or medicine, and what ever will entertain us for the flight like books, magazines, ect. The 1st time we flew w/ the girls my youngest was 3 we forgot to tell her about the xray machine and when it came time to put the bag through it she through a fit , poor thing thought they were taking away all her special things. So just explain it and stress that they will get the bag right back and this will work out great.