Never is a pretty bold statement, and obviously this depends on the length of flight, but here goes:
Cabin humidity isn’t just for your insides. Though this product has been relabeled as Cactus Flower & Tibetan Ginseng Hydrating Mist, I have been assured it is the same stuff. I spray this stuff liberally on my face and neck, and honestly anywhere else. It smells great and a bottle lasts forever. Make sure you buy the 2.5 oz size because this is a carry-on essential. Who checks bags anyway? Things are better if you’re on a 787, but I still bring it.
Blanket, headwrap, skirt, privacy shield…what you can do with a scarf is endless. I recommend something at least 6 ft long and 3 ft wide. Linen is great, cotton blends are great, silk is ok. Fold it up, wear it on, whatever. If you’re in economy, make yourself a little privacy sleeping hood. Anything that makes you feel a little less like you’re mere inches away from the face of a stranger.
Sure- most planes will give you free water. But it is never enough. Seriously you need to drink more water on planes. One liter for every four hours of flight, even more if, like me, you love to drink the free booze. I do this even when I am in premium cabins, as it is personally more annoying to continually ask for water or deal with trying to hoard mini bottles at your seat than to just bring some of your own. Water sacs are nice because they flatten and are reusable, but if push comes to shove, buy a liter at the airport. If I am going to a destination where the tap water is not drinkable, I will bring one with an attachable purifier.
4) Thick socks or slippers.
My shoes are coming off but I am not going to walk around the cabin in my regular socks. Slippers are ideal- better protection from the floor, but socks are easier to pack. If I am in business or flying economy on airlines like Qatar or Korean, this will be provided. Always be prepared though.
5) Noise cancelling headphones
I like these, which are small and I can crumple up and abuse. I can’t sleep with giant domes on my ears. I also love that you don’t have to charge them. Remembering to charge your electronic devices before leaving is obnoxious. Between computers and cameras and phones and battery packs, the last thing I want to worry about it my headphones.
Disposable face wipes, toothbrush/paste, eye cream, and a non-aerosol dry shampoo are my runners up.
No, I don’t receive compensation for this but I am totally open to product bribes.