Zithromax is a wonderful invention.
As a parent of frequent ear infection sufferers & a sufferer myself I just wanted to make you aware that there are prescription numbing drops for the eardrum that would be a great help IF the ears act up. For some reason no Dr ever gave these to me even though I've endured decades of ear infections

One year, 2001 to be exact, DS had an ear infection that didn't clear up in the normal 5 days and his fever kept rising & his pain kept increasing. Turns out he had a resistant strain so the Dr gave us the drops to make him more comfortable...all I could think is "Why did it take this long to get it?"

Ear infections HURT, take it from an adult who still gets 3-5 a year. Since getting these drops the first time I always ask for the drops as a additional prescription 'just in case' the antibiotics fail or the flight is too much. They are called "Antiprene & Benzocaine" as a generic and work very well. Just be warned that they can mask a serious problem so they should be used VERY sparingly as in only for the 1st 2 days of treatment or just before takeoff.
Have a wonderful trip