I agree w/ pp's
We just traveled a few weeks ago (3 hour time change) and it didn't do anything.
We just went with the flow. For the most part she actually stayed on track time wise...minus "early" wakings....she was up 8am their time, which was 5am our time, but it all worked out and we just made sure to not stress, because there's really nothing you can do.
She did well there and then got right back on track when we got home, which I didn't think would happen.
They do surprise us sometimes, thankfull
Also, DD is very spirited and hates to be confined, however on the plane she's an angel.
We had a 2 hour and then a 6 hours flight back to back (no running around time)...I thought we would all go crazy.
We bucked her into her car seat and she read and watched movies on the portable DVD player. We only unbuckled her to change her pull up and then strapped her back in. She had no complaints.
Bring lots of snacks and anything really familiar to them.
Have fun!