Asklemmy

Get a pack of cards and learn some fake shuffles (via YT) then memorize the 673 King Street trick.

ETA a much better performance.

I would recommend eating. Try a few places. That always passes the time for me.

Buy books? 20 hours man, I could burn through at least two.

Just in the Android games thing, a couple of recommendations:

• Golf Blitz - very fun crazy golf game which does have IAPs but they're not at all necessary to progress a long way in the game (in the very upper levels, it gets a bit slow as you need to build XP, but I've been playing it more than a year and never felt tempted to buy my way up the ladder. It'll certainly provide entertainment for a few hours. Does need an online connection though.

• Antiyoy - very simple strategy game that starts easy and gets very tricky. It's fun and no connection needed. Over 170 official levels, plus a whole bunch of user levels of varying quality. No IAPs at all as far as I remember.

The best advice of keeping moving has already been suggested, but buy a real book, and maybe a crossword or other such like. Avoid technology.

Uhh, start drinking?

Go exploring. Walk the airport and go to other wings if it's a large airport. You might be able to find a luggage locker so you can walk without carrying anything.

In the same line, there are a lot of games that gamify walking. One. Two. The goal here is to exhaust your body a bit better for the 13 hr flight.

Learn something. A new language, maybe. A skill. Learn braille and go around the airport decoding the braille signs.

Do an airport scavenger hunt. Can you find yarn and maybe practice finger knitting? Maybe a deck of cards and learn some card tricks?

Talk to people. Honestly I'm an introvert so I rarely do this but it can be fun.

Do you like Roguelikes? Slay the Spire is really good and it's on Mobile.
It's a port from PC, so no microtransactions or garbage like that, one purchase and done.
There's also Mindustry. It's a mix between Tower Defense and Factory game. This one also has no MTX since it is a Open Source game. Free on Android, 2 Bucks on iOS.

No advice, but I sympathize. I once sat listening to music while waiting for my flight to board. When there was no activity and fewer passengers in the area than I expected, I discovered that while I had been waiting they changed the gate for my flight. I ended up waiting in Chicago Midway (this was before their big upgrades in the early 00s) for 12 hours. It was hell.

There are very good mobile games without subscriptions, virtual coins, loot boxes and shit. Some examples on iOS:

• Sawblades
• Ollies Arcade
• Knotwords
• High Rise

I would say get a hotel room, but it has uh, been 6 hours since you posted this so…

It may sound stupid, but try learning some card tricks or play solitaire with some playing cards?

Twist your thumbs

Try Monument Valley it's a one time pay puzzle game that moves like an MC Escher sketch.

you can't kill an idea

I wouldn't get wasted, if you're in your 30s that can give your worst headache ever. If the wifi is good enough, maybe start a series? Possibly something with short episodes, a well-selected anime will easily kill something like 10 hours. And if possible, try to get as much sleep as possible

You could watch The Terminal 9 times back to back, and have just enough time left to be disappointed by some overpriced meal at the Wolfgang Puck.

I know you mentioned audiobooks but what about some digital books? Personally, reading makes my eyes tired so I know that, for me, reading something would be a good way to provoke a nap.

As a response to the idea that you may get fatigued by passive media, a book may be a good balance to that. With movies, shows, and audiobooks, you're going to be listening the whole time. It's just constant noise. A book may be more meditative.

Which reminds me, this may be a good time to practice meditation.

The most addictive and a complete experience in your pocket kind of game is Crashlands. It's amazing if you're into games where you have to craft things to survive. Definitely recommend giving it a try.

Puzzle books? I like to play with variety puzzle books, commonly sold near magazines :3 Crosswords (and varieties thereof), word searches (+varieties), crypto puzzles of various sorts, number puzzles of various sorts, the funky neat ones where some of the words share some letters (like, a letter fills a vertical region to be shared by one or more words), uhhh... oh also I like to write the solutions in Thorass :D https://forgottenrealms.fandom.com/wiki/Thorass_alphabet Though the numerals are garbage. D'ni numerals are far, far better 👍

Also, I daydream for hours at a time. ... But probably you don't or else you wouldn't be asking for ideas I guess 😅

Bloons Tower Defense 6 is a really good game that you could sink time into! It is paid, but I highly recommend it

It's a damn shame that you can't go to a pharmacy in the airport, tell this tale, and get some xanex to zonk out and time travel to your destination.

It's not gonna last you 20 hours, but last I checked the official Sonic 1, 2 and CD ports are all free on mobile (and they're really good).

As for android games, if you're into tower defense, give infinitode a try :)