I appreciate all the feedback - unfortunalty Benadryl makes my darling 18m old daughter (will be 21 months when we travel) into a nut bar, which would not be a good thing on a plane, and given that she is so young, the chewing on gum is not helpful.
She is also not been using bottles for since 10 months, and truly, she can't drink for the entire descent. I am looking for alternatives that will help a toddler who does not take a soother/bottle/chew gum or take meds.
Maybe i will buy the earplanes ahead of time and just see if i can get her to wear them around the house, to get use to them.