I took my son to Hawaii when he was 9 months old. I found that he didn't sleep much on the plane. He was quite happy to crawl all over the floor. In fact, quite determined to do so. Fortunatly people weren't up and moving about so I was able to let him explore a bit. I ened up carrying him up and down the aisle for about an hour before he'd take a nap. At least I didn't need to worry about DVT from being stuck in my chair.

In terms of jetlag. I found it very helpful to get a schedule set from day one and stick with it. For us that meant being back at the house we were staying and having regular nap time from day one. No napping in the car or while we were on the go. We did our usual morning routine just as we would at home (a walk, play at the park), meals, naps, more play and meals, then to bed. On other trips when we've been more lax with the schedule we've had a lot more problems with jetlag. The predictability seemed to be hugely helpful to helping my son adjust to the time difference.