I have been flying with my dogs for years and even with this little pup I have had no problem and no need for meds. They tend to sleep.
My vet will not recommend any meds because he says there is problems with the pressure. He says that you can't predict what will happen. I don't know if it was because my dogs were under 5 lbs or what.
I too, recommend that light food, light drink. Exercise them GOOD before the trip so they are ready for a nap.