Ear bud head phones
When I fly I like to wear simple ear buds which fit snugly in the ear and are not uncomfortable when leaning on a neck pillow or the window like the big headsets can be.
If you don't have a set of ear buds with your cell phone, then I have bought these in. They have a curved shape which I find sits better in the ear than the round ones and they fit into universal head phone sockets so can be used with your phone, iPad, laptop and the entertainment system of most (so far I have found all) air planes.
I actually use these ones everyday for great sound when listening to music and podcasts when I go walking and they also have a microphone so you can make handsfree phone calls too.
Three colours: mint green, blue and white