We fly a twin engine and both our kids have flown since they were 3 months old.
I was also worried about their little ears. I would put their hood up and wrap a blanket around their head so it covered their ears.(this was when they were in the infant seat and they still couldn't support their heads.) My daughter did get airsick once when we flew to Arizona, but it was really bumpy. Now that they are older I give them dramamine. We have flown from MI to AZ with our kids that young. They have no hearing probs whatsoever and the oldest is 5 now! Good luck--oh and we also flew into Kissimmee last year to go to Disney, I'll have to ask my husband what fbo we flew into. It took us forever to get a taxi!!