The realities of modern-day air travel mean you need to fly defensively. Pack knowing things will be less than ideal. First up: Bring your own water and snacks on board. If you're seated at the back and turbulence slows down the service, it could be hours until you're served.
Is the plane temperature going to be too warm or too cold? The answer is likely all of the above at one time or another. And heaven help you if you're stuck on the tarmac. Dress in at least three layers: a thin T-shirt or tank, a long sleeve and a sweater. You will be the envy of other shivering/sweating passengers.
Do your research. If you need to download an app to watch the movies, do it before you board. Don't count on the seatback screens: If the system goes down, you don't want to be on a 14-hour flight to Shanghai without a backup. Buy a cheap airport paperback, pack a deck of cards, anything to preserve your sanity.
Air travel is incredibly dehydrating. The general rule is drink a glass of water each time it's offered. And if you don't want to look like you've aged 15 years when you land, slather on the face cream – or, even better, a mask – and treat your hands and arms to lotion as well (especially after using that inevitably drying bathroom soap).
You don't need to buy pricey noise-canceling headphones – but you do need to bring something to muffle the crying babies, send a clear signal to wannabe chatty seatmates and drown out the singing of the drunk woman across the aisle (yes, it happens). Any headphones playing music or white noise will work, and even cheap ear plugs will help.