(These from Trip Advisor with smi additions)

• Pack light to travel light. If you can manage with a carry-on, do it. Try taking half of the things you need and twice the money. You can make buying a few new items a fun part of the adventure.
• Bag it. Kitchen sandwich bags can be used to hold your accessories, vacuum pack bags can be space savers, and trash bags have multiple uses (laundry bag, shoe covers). Use bags to hold clothing (e.g., ziplocks and shopping bags, put all shirts in a bag, slacks in another, this way they slide around rather than forming creases.)
• Create compartments. Two words: packing cube. If you are visiting more than one city during your trip, packing cubes will keep your suitcase organized and save you from having to pack and unpack.
• Bring a multi-socket extension cord. Although newer hotels have USB ports in rooms, it’s best to have an extra outlet to charge all of your electronics at once. Also bring along an electric extension cord with 3 plugs, you'll need them.
• Pack a sleep mask and ear plugs. These can come in handy on a plane, train or in your hotel room.
• Share your packing space. Traveling as a couple? Split your clothes between two suitcases on the off chance one of them gets lost during the flight.
• Make photocopies before leaving home. If you’re traveling out of the country, make two photocopies of your passport. Use your smartphone to take pictures of your car in the airport’s parking garage and do the same for your luggage and its contents in case it gets lost.
• Put a dryer sheet in your luggage, keeps things smelling fresh.
• Universal packing list You select what you want to bring, it'll create a checklist
• Roll pair of socks into a ball for easy packing
• Heck, roll up all of your clothing rather than folding

From https://lifehacker.com/how-to-avoid-getting-the-flu-on-an-airplane-1822265077

• Pick a window seat. (else get germs from all walking down the aisles.
• Wait to board. (Avoid large, tightly packed together groups.)
• Stay Hydrated.
• Turn on overhead vent. (moves germs in your vicinity away from you.)
• Wipe everything down.

You can get early access to the plane by saying you have a peanut allergy and need time to wipe down the seat area.

Very unlikely it'll happen, but just in case.
How to survive a plane crash
In brief:

• Sit in the back of the plane. Within 5 rows of an exit door. Count rows to the exit.
• Wear cotton and wool. Tie-on shoes, long pants/jeans.
• Wet a hankerchief, put over your face, is temporary breathing mask
• Be wary within: 3 mins of takeoff, and 8 mins before landing. No sleeping or music; wear your shoes.
• Crash imminent: tighten seatbelt; cross hands on seat in front, rest head on hands (prevents whiplash & head injuries), wet hankerchief.
• After crash, get out! Get away from the plane!

Youtube video
In short:

• Under the insert in your gym shoes
• Inside an empty dental floss container
• rolled up in a partially used toothpaste tube
• Inside a deck of cards (remove inside of 3-4 cards)
• In a chapstick
• rolled around the ink in a ball point pen

You're in a hotel or a room somewhere and you want a cheap way to securely keep the door closed so even those with a key can't get in. Door lock out of a dinner fork
Commercial door lock on Amazon abt $22

from Katherine Maher, international geek via Quora

1.  Never check luggage.
	• It's not just that it gets lost. Not checking means you can switch  flights in a pinch, whether for a more direct connection, an upgrade, or  to take a voucher for a later flight when they get full. 3 weeks on 1  bag is totally possible!
	• Learn how to roll. The NYTimes has a great demo here: http://www.nytimes.com/2010/05/0...
	• Prepacked travel kits (see below). Wet bag for toiletries, dry bag for meds/sundries, and business kit. Replenish after every trip, store together.
2.  Plane - Pack a business kit for coach
	• earphones
	• plane socks - pressure socks for  long hauls - DVT is no fun. regular socks for plane-only wear keep you warm if you stupidly wore sandals, and lets you run to the bathroom without shoes, without getting regular socks grimy.
	• inflatable neck pillow
	• eye mask
	• chapstick
	• pen
	• mini toothbrush/toothpaste
	• earplugs
3.  Health 
	• ibuprofen/aspirin
	• Cipro
	• Benadryl
	• Neosporin
	• 30% DEET mosquito repellent - anti-malarials are miserable. use DEET, wear light colored, long clothing, and be careful instead.
	• oral re-hydration salts - get  better fast after food poisoning (also great for hangovers)
	• condoms
	• band-aids
	• SPF30 or 50
4.  Toiletries:
	1. Buy a clear hard plastic regulation size bag.
	2. Buy a set of 3oz/100mL refillable bottles. buy only the kind with 3 OZ or 100mL stamped into the plastic. some airports will not accept unmarked bottles, even if properly sized, and printed writing wears off. I learned this the hard way (I'm looking at you, Dublin).
	3. Fill them with your standard products. you will never need more than 3 oz for 3 weeks, and probably longer.
	4. Fill your bag with your bottles. 
	5. Fill a pencil case or similar with cotton balls & Q-tips (& tampons, etc).
	6. Leave in your suitcase. Refill when necessary. Never worry again!
5. General
	• notebook, w/ mini paper map of destination city and all critical phone #s
	• unlocked GSM phone - skip the roaming bills, get a local SIM
	• shower sandals
	• sunglasses
	• medium-size square scarf - warmth,  coverage (for women), makes a dirty seat instantly clean.
	• packet of clothing detergent - wash & wear
	• string - tie stuff up. turn a shower into a clothes line. string is awesome. 
	• duct tape
	• zipties or twisties
	• 4-5 ziploc baggies
	• pocket knife
	• bottle opener
	• uniconverter
	• mini flashlight, LED are best
	• 2 AA batteries, 2 AAA batteries
	• tissues (the little plastic baggies)
	• gum for when you can't brush your teeth
	• granola bars
	• Visa - it's true - it's everywhere you  want to be. MasterCard is often not.