What would you not be without on a long flight?
 

My 'must take' plane travel items: (12 hour flights, you betcha)
1) Small goose down pillow, crushed down into flexible courier bag for carry on (same pillow I sleep on at home, so no need to sleep on those foam cubes at the destination hotel)
2) Ear plugs. Silencio brand, silicon filled, conform to your ear. The twins behind me screaming their heads off can't cut through these.
3) Bose noise cancelling earphones. Much better sound than those provided by the airline and cut the exterior noise at the same time.
4) Kindle, loaded with good books.
5) Sweatshirt to wear at 40,000 feet when you can't turn off the a/c.

What else would you never be without on a long flight?

Pashmina, some chewy candy (fruit mentos are my go to, which is odd, because I really don't eat candy as a rule!), some tv shows or movie on my phone in case I don't like / have seen / IFE or it is broken, my own big bottle of water (nothing annoys me more than mini water bottles / foiled cups), a pen, painkillers, and a full washkit with cleanser, toner, moisturizer, lip balm, toothbrush and paste, eye cream, eye drops, and a vicks type inhaler.

Phone and laptop chargers, my own IFE when I'm stuck in the back of yet another crappy UA 747, music and headphones. And a pen. I hate having to scrounge one right before landing for customs forms. Ought to start carrying a water bottle, even after all of the mini-bottles and dixie cups, that'd never occurred to me.

I don't really bother with devices anymore, given that I already have to lug around a laptop, why bother with yet more weight in my bag?

I thought I could keep this simple:

iPad, Beats headphones, and a couple energy bars.

But then there's the supporting elements... chargers & my outlet splitter for layovers. A book for incase it gets that delayed. Bubble-gum to fend off a bored kid. Sweathshirt if I'm not headed somewhere warm. Trail mix if I skipped a meal or it's that long.

In the end I take the same backpack about anywhere... it's pretty full and while I don't use half the stuff on any one trip it all gets used across a few.

Drugs, drugs, and more drugs. No way I want to chance being awake on a flight over 4 hours.

chapstick ... my lips get so dry in the air.

I define a long flight as transpac or transatlantic.

iPod with extra battery
Bose QC15
Alcohol
Laptop (uses same extra battery as iPod)
Pen (nothing I hate more than not having a pen to fill out the arrival card)

Pen (International Flights)
Book/Magazine.
Headphones
Ipod/Iphone
Gum (for obvious reasons)

This is my usually survival kit. I tend to sleep for half of the flight and I have more than enough entertainment for the hours I am conscious on the plane.

If we are talking about international long haul flight, then passport. :D

Magazines [best time killer]
Jacket [airlines get really cold sometimes]
Laptop[ great, if there is wifi on board ]^

iPod, Bose QC15s, a nice comfy hoodie, pen, essential toiletries, a change of sweatpants for the flight.

At least two pens*
Sudoku book
Magazines
Lip balm (Burt's Bees is my preferred brand)
A bag of almonds (either Jordan Almonds or cocoa-roasted almonds)
Sugar-free Coffee Nips
Gum (Orbit Spearmint)
Eye drops
Mints

*Thanks to the thread starter for reminding me to replace the pens in my carry-on bag. On my last flight one pen developed a nasty leak and the other got lost, and I'd completely forgotten to to put new ones in my bag until just now.

Crossword puzzles.

Ear plugs
Sweater or fleece jacket
Enough to read
Eye shades
My carry-on(s)--I almost never check luggage

I suspect that by next year the list will include an Ipad with movies downloaded on it, but for now on international J I'm fine with IFE and on domestic I'm indifferent to IFE.

netbook
mp3 player
vodka