Two things make any long flight seem short: comfort and distraction.
My personal longest was 24 hours from Cape Town to Heathrow via Johannesburg and Istanbul. But then, I’ve been on sub-5 hour flights with fellow passengers lamenting how it was “such a long flight.” It’s all relative. No matter your definition, there are two keys to making any long flight seem short: comfort and distraction. 

Here are 5 items to help pass the time and air miles.

Movies, music and more

Every major airline, and most of the smaller ones, have seatback entertainment. Generally these are of the on-demand variety, letting you choose from a variety of movies and TV episodes. But will they be the movies and TV shows you actually want to watch?

You’re probably better off bringing what you want. Netflix, Amazon, iTunes, Vudu and others all have mobile apps that let you download content to watch offline. If you paid for the movie or episode, you shouldn’t have an issue downloading it. If it’s Netflix, or included with Amazon Prime streaming, there’s no guarantee you will be able to stream anything from these services on the plane, even if you pay for the in-flight Wi-Fi. You’ll probably have a hard time downloading at the airport too, so this is all something best done at home.

A growing number of airlines are doing away with seatback entertainment and instead offer the same content via their own app, streamed internally on the plane’s Wi-Fi to your phone or tablet. Check if your flight has this beforehand or be prepared to download the app at the airport before you board.

Charging cable and battery

Since you’ll likely use your phone or tablet for a good chunk of the flight, you’re going to need to keep it charged. Long-haul flights usually have an airline’s oldest planes, so you can’t be sure if there will be a power or charging outlet available at your seat.

SeatGuru will help with this. The site gives you information about your specific plane, and even about the seat you’ve selected or been assigned. No matter what’s available, you should keep a portable charger with you. 

Noise-cancelling headphones

These reduce an incredible amount of noise. Options are over-ear headphones or  just use earplugs (which many airlines provide in amenity kits). However, those rely on getting a good seal between the plugs and your ear canals which, on some people isn’t easy. 

Layers

I’ve never been on a flight that had a steady or predictable temperature. It’s pretty much impossible, given the cold air outside, the humid, heat-producing bodies inside. Layers are key. Some airlines will give you a threadbare blanket to “warm” yourself if it gets really cold, but I’ve never regretted bringing a hoodie or pullover. Worst case, it doubles as a pillow. 

Different parts of the plane will also have some effect on the temperature. Window seats are likely cooler than aisles, and exit rows cooler than all others.

Anything you need for your personal comfort

There is a massive market for in-flight comfort products. Most are pretty useless. For example, if you only fly once or twice a year, spending money on a travel pillow probably isn’t worth it. 
Most airlines on long, overnight flights will give you a sleep mask and a small tube of moisturizer. Airplanes air gets very dry, and even at night there are lights around the cabin you might find distracting.

Usually you’ll get a bottle of water for free, but if you’re the thirsty type, bring an empty water bottle and fill it before you board. 

Lastly, a pen is handy. If you’re on a long flight, chances are you’ll need to fill out some sort of customs or immigration form, and airlines never have pens.