I get seasick, car sick and altitude sickness and I found that 1/2 Bonine at night does the trick for me and my daughters. If I take a whole Bonine, I am too sleepy.
I received confirmation from our pediatrician that we could use 1/2 of any over the counter motion sickness medicine for them if needed. I just tried the 1/2 tablet and it works with minimal sleepiness.