H.W.
My mom and I flew to Texas when my daughter was about 16mos. She's a wiggle worm, so I took her car seat and was glad I did in spite of it's monsterous size (bless her heart- my mom hauled that thing through LAX). A few weeks before the trip I had my daughter pick out some new toys and books at the store, giftwrapped them, and hid them until we were up in the air. Actually, as soon as we were airborn she went right to sleep. My brother-in-law, an airline pilot, explained that because there is a little less oxygen at take off, little ones tend to conk out pretty soon. I know that sounds creepy, but it was amazing how quickly was she out- it was fabulous! If at all possible, try to request seats behind the bulkhead. There's a lot more room.