I fly twice a week, but always under 2 hr flights. (although often they are extended due to lack of gates at ORD).

I am taking my first trip across the Atlantic in a couple of weeks and I am nervous about being cramped in a coach seat for 9 hrs, I am just over 6 feet tall. Does anyone know if I make an appointment with a doctor, will he or she prescribe me something to knock me out for most of the flight?

Thanks.
-matt