answer:Bring an empty sippy cup and fill it once you are on the plane. If your toddler get very cranky while the plane is ascending or descending, it may be the discomfort caused by the pressure change. Have your toddler sip the sippy cup during ascent and descent to equalize pressure in the inner ear. Use portable video player (iPod, PocketPC, Zune, portable DVD, etc.) and prepare a few cartoons for your toddler to watch during the flight.