Meclizine
"After years of suffering motion sickness, I finally tried Bonine.  I've been taking it for about 2 years now for car rides longer than an hour and plane rides.  For me, it only works if I take it at least an hour before travel.  If I take it when I'm already sick, it only works about 50% for me.  This wonderful medicine has allowed me to travel.  Before, I used to dread going any distance.  I do get a little bit drowsy, but not to the point where I cannot function.  I can still work, sight see, etc.  I sleep wonderfully when I'm on it!"