Not an expert by any means, but I had no problem last May. I was supposed to leave from Philadelphia a bit earlier, but instead left around 9 pm. I had a glass of wine before boarding, had their meal on the plane. As soon as that was done and they turned down the lights, I put the seat back a bit, put on earphones, covered up, used a neck pillow, but put it under my chin (keeps your head in better position and your mouth from falling open - haha)and donned a sleep mask. I must have looked a sight, but I knew no one on the plane and I slept soundly until the bustle started for drinks before landing. I arrived fairly well rested in London. I think I also slept a bit from London to Madrid, but did not doo anything special for that flight. I arrived wide awake and ready to go. I will try that again this May when I head back with my husband to see Juliana graduate.