Flying with a baby! (Advice pls)

I'll be flying (for the first time) alone with my 7 month old next week and I'm looking for advice on a smooth travel! The plane ride is a little less than 4 hours long. I already plan on bringing the basics (diapers, food, teething medicine) but I'm nervous I'll forget something! Any advice would be appreciated. Also should I be worried about his ears and is there anything to help?