We had to get up at 4AM to catch the plane. Actually, me and my wife got up at 0330, since my son started crying. We were afraid he was going to have ear pain on the plane, and of course that is what happened. Only it went away when I blew his nose and netted a ton of yellow snot. Yes, of course he had a nasty infection and we had already taken him to the doctor. You should always do that if your kid has a problem before traveling, no matter what it is. Stomach ache, ear-nose-throat, anything which can detract from the pleasure of travel should be treated. It is unlikely that it means you can not go on that vacation, except if your child has a high fever. In that case, you had better made sure you can cancel the ticket without cost, either due to the terms of the booking or because you have cancellation insurance. You do not want to toy with a fever, even if it is something which goes away after a day, since it can be life- threatening in a toddler.
Depending on where you come from, you will have different expectations on the cure. In some countries the kids get antibiotics only with a runny nose. In other countries the expectation is that a childs fever will heal itself, no matter that they have to stay in bed for several weeks.
To be honest, the antibiotics that allow the children to get back to daycare or school are mostly prescribed for the convenience of the parents. Our son had a fever that would have merited him a generous dose of antibiotics in Japan, but in Sweden the philosophy that if the child does not have a life-threateningly high fever, it will heal itself after a few days. And it took a week until the fever broke and he was back to his old self. If we had lived in Sweden, we would have enjoyed the generous allowances for parents staying home with sick children. But now it just forced us to slow down and stay at home. Well, we were on vacation.
But if they do not have a fever, then a kids decongestant will make sure the finer passageways of the nose and ear do not get inflamed and swell up so much that they close pockets inside the tissue. When the pressure changes the air or fluid in these pockets (or inside the inner ear) expands since the air can not get out, and this hurts. You have to have had sinusitis to appreciate how much. The screaming can be awful.
i have written before about flying with toddlers as well as flying with infants, and started a series of posts about our experiences from our longest trip yet. And about beating jetlag with toddlers.
There are various tricks to relieve the pressure, which may help unless the child is actually sick - in that case, only decongestant helps. Making the child swallow is the easiest way to relieve ear pain (and sinus pain too). A small child can use a sippy cup, which is an exellent way of making them swallow which opens the inner ear, relieves the pressure, and unfortunately also makes them pee more and may not last that long.
With small kids you can also try the paper cup trick, where you place two paper cups with wadded up paper soaked in boiling water inside the cups. The idea is that this will decrease the pressure as the heated air cools, and this will make their ears pop.
When they grow a bit older you can give them candy, or better yet lollipops. Sugarfree will not be a danger to the teeth of your kids. But no less effective.
I am Wisterian Watertree, recently moved from Tokyo to Sendai, previously of Bangkong and Honolulu. I write about travel, especially with our three beautiful kids (two girls and one boy, soon turning seven - yes. they are triplets). Travel is education and fun rolled into one, and if you are like me, that is something you want to give to your kids. If you want more tips and want to find out when I will publish something, get it from my email list. If you want to be personal, drop me a note on email@example.com, or if you want general tips, follow me on Twitter @wisterianw.