M.M.
If I were you I would talk to the Dr. and make sure she had NO fluid on her ears before you fly. Ear problems can make for an extrememly bad trip if the pressure builds up! I have also recently read that portable DVD players work wonders on small children flying. If your daughter likes to watch cartoons, I recommend taking one with you. Another idea is to look at the different airline websites and get advice from them. They have a ton of experience, and probably have some good recommendations.