My wife won't fly without them and as long as you keep them clean, you can use them for 2-3 round trips without an issue. Someone already mentioned that you really want to put them in before takeoff and an hour before landing as the pressure starts to build before you feel the plane descending. Another thing is that in order to get the good seal you really have to get them into the ear. The trick is to tug on the ear with one hand and insert with the other.