Mount your phone, insert your headphone and play a movie :) Surprisingly, this mount held really well even against turbulence during the flight. This mount will work well if the seat in front of you is upright. Once declined, the viewing angle is compromised.
Another option is to always bring a portable suction type phone mount (http://blog.alienskin.com/wp-content/uploads/2010/12/Kensington_Mount.jpg) with you while traveling and sit beside the window so you can fix the phone on the window in front of you while on flight. I was able to use this for a few flights but the DIY barf bag project was more interesting and challenging :)