I fly around 100-120k miles a year so aircraft have become a place of rest. Simply sitting on one usually puts me to sleep.

That said, I take a number of very long trips each year e.g SYD-NYC etc. and find that ordering 2 or 3 rum and cokes after dinner and diving under the blanket knocks me out for a good 8 hours. Steering clear of the in flight entertainment helps too - plain old reading is much more calming.

Never used a neck pillow as I've always found the adjustable headrest to be adequate.