Whenever my kids were over-sugared, I did what my Mom did with us and what my Grandma did with her - a cup of warm milk with a tsp. of honey. They slept like babies and my daughter now uses this with my grandson whenever he is over-stimulated.
Airplanes have microwaves - ask the flight attendant to nuke the milk, though I doubt they have any honey. In the future, you may want to carry it in your carry-on baggage though you'll have to put it in a 3 oz. container and then insert it into a quart size Ziploc bag and hold it while going through the security checkpoint, but hey - it's worth the P & Q!