This is a bit bizarre, but bear with me.
My most comfortable long-haul
ever was a 2-day trip in a C-130 Hercules from RAF Lyneham to Little Rock AFB. I have a string hammock, and with the Loadmaster's permission, I hang it from the aircraft frames right at the top of the rear ramp. It's a bit cold up there [you actually get ice forming on the inside skin], but wrapped in a warm jacket, and wearing gloves, you settle down.
You then discover this gentle swaying motion. The rudder is compensating for this, and the ailerons are compensating for that ... and you sway. Gently, endlessly, rocking in mid-air. I slept nearly all the way from Lyneham to Goose Bay, and most of the way from Goose to LR. It was simply lovely.
Oh, I forgot to mention wearing the ear-defenders
