Travelers are particularly vulnerable to sleep disruption when their trips takes them across two time zones or more.
The typical circadian window is open from 11 p.m. to 7 a.m. is according to Johns Hopkins Center for Sleep Medical Director Charlene Gamaldo. But it can slam shut at other times when traveling great distances across multiple time zones.
It's best to try and adapt to your new time zone ASAP. So if you're travelling east and landing early, do your best to sleep on the plane, remain active during the day and aim for a normal bedtime.
A dose of melatonin a couple hours before you turn in can help with the transition. It's not a sleep aid per se but helps your body produce the natural melatonin that can aid in resetting your body clock.
On the flight, comfort is king. Dress in layers. Loose clothing works best. In the coach section, where space is limited, window seats provide a few extra inches and something to lean against. Recline the seat if it's more comfortable. Those neck pillows really do help stabilize your head so you're not bobbing awake. Versions made from memory foam are easier to squeeze into luggage.
Other items that help some travelers are eye masks and glasses that block blue light emitted from cellphones and tablets. If you're reading on your tablet, utilize the dimmer or controls to reduce the brightness. Earplugs or noise-cancelling headphones may make a difference too.
And though a lot of people don't want to hear it, alcohol is a double-edged sword when it comes to sleep. It may induce drowsiness, but it also disrupts the ability to stay asleep and can contribute to snoring, which is not annoying to others aboard the plane.