Be careful with Benadryl. You may get recommendations to use it but kids can react two ways. They can fall asleep like little angles and not bother anyone or they can turn into a hyperactive creature that will make you believe possession is real! I flew to Egypt with my infant nephew once. If the flight is not packed that is fantastic. Room to move helps a ton. Have the favorite toys, books, and movies loaded on iPad or iPod with headphones. We lucked out and our flight to Paris for the connection wasn't packed and had a whole row he could play in.