OK, I know we go through this every winter- it snows, air ports shut down. But that is mostly in the States, where if you really, really need to you could find alternative ways to get home, but it is looking like some of the travelers stuck in the UK could be there until almost the new year.

So how to you prepare for that? Lets say that for some reason (paranoia, snow drift, laziness) you can't get to your checked bags for the first two days. So other than your papers, two good credit cards and cash, what would you have in your carry on. Assume you have to shelter at the airport.

BTW, cheers to the french for bringing in cots, boos to the germans for bringing in clowns.

Top choice, hands-down, is my iPhone. After that, underpants, socks, toothbrush, toothpaste, contact lens stuff, glasses, reading material, iPhone cable, laptop.

I just came back from an international trip that included plane changes, taxi rides and boat rides. I carried all of the things below:

-large laptop bag
-floss, toothbrush, toothpaste
-camper's toilet paper (Walmart)
-extra undershirt, underpants & socks
-bandana
-laptop
-cell phone
-chargers
-adapters
-AA & AAA batteries
-regular survival kit: flashlight, Bic, whistle, mirror, paracord, basic First Aid, etc.
-leisure reading
-beanie
-sun hat with wide brim
-hooded ski jacket (on me usually)

If I'm traveling through frigid airports, I'll carry clothes for cold weather. I've had my luggage get lost before on a stop through Denver I think it was. I had to spend the night in the airport because I missed a connection. The heat shut off for several hours in the early morning hours. When I travel with my fiance, I have to double up some things. I expect her to carry none of that stuff, but of course she still expects me to have what she needs.

I may sound lame for saying this: I don't enjoy air travel anymore. It's too complicated. If I can get similar enjoyment by driving somewhere local, then I'd rather do that.

Years ago, I was told that your carry-on bag should contain just about everything you need to survive at your destination should your main bag get lost (or you end up stuck at the airport for a while).

Therefore, besides cash, a cell phone, and identification on my person, I make sure my carry-on has:

1. Some extra cash.
2. Spare change of appropriate clothing (I usually pack jeans, a long sleeve shirt, underwear, socks, and a hat)
3. A water-resistant jacket
4. Basic hygiene supplies (comb/brush, tooth brush, wet wipes, ect)
5. Water and snacks (used to be able to bring through security, now must be purchased post the security checkpoint)
6. A battery powered Am/Fm radio with earbuds (to get up to the minute news regardless of whether cell phones or wifi is working).
7. Something to keep you busy for a day or two (i.e. a good book, ect)
8. A pen and paper
9 Basic first aid stuff (band-aids, gauze, OTC medication, as well as any necessary prescription medications)
10. A flashlight
11. A Whistle

I used to be able to carry a small Swiss Army knife in there as well, but now I have to put that in my checked bag.

I just hate that I can't check only a pocket knife. I typically pack in a carry on size bag but end up checking it to get my leatherman through.

Ultimately, what I carry on me everyday supplemented by a phone charger, a water bottle, and glasses would suffice.

My usual travel vest containing:
Cell phone
cell phone AA-battery charger
Nano iPod with built-in FM radio
prescription medicines
heatsheet
deck of cards
paperback book
toilet seat covers
aspirin
gum
toothbrush, toothpaste, dental floss
digital camera
small notepad
pen
business cards

With that stuff I can contact people, be entertained, make friends, stay abreast of news, and wrap myself up. That's good enough for me.

-Blast

As others have said, it's not just getting snowed in. My wife and I used to fly down to the French West Indies, and occasionally our baggage didn't make it with us. One airline had only 1 flight a week to the island we were on, and all we had with us was our carry-on luggage.

We carry all our necessities in our carry-on nowadays, which includes a change of outer clothes and a couple or more changes of underwear, shoes, medicine, toiletries, and whatever we'll need for at least a couple of days. A cell phone is a necessity when traveling these days, along with it's power cord, an extension cord, and plug converters if we're going to the French West Indies. I generally also take a netbook with WiFi and power cord, too.

In this weather, we'd have our winter coats if we were going to be on the East Coast or Europe. I'd hope for food at the airport.

Adding to the above;

fleece top ( warm and comfy)
water bottle
phone/ phone charger/ earphones / battery
Snacks/ food - mostly balance bars

Money belt.

Afll of the above - also, after spending a long 12 hours in Iqaluit airport a few years back without a hotel (think Nunavut, way northern Canada, Baffin Bay etc), I now pack a sleeping bag liner in my carryon. And if I have room, I also pack a sleeping pad, I have an inflatable Big Agnes that packs small but blows up and is really comfy to sleep on. The sleeping bag liner I think is way more comfortable to sleep in than throwing your jacket over your shoulders. They come in silk (popular), fleece, flannel, and cotton, and run maybe $30-60 before sales - http://www.rei.com/search?search=sleeping+bag+liners&seq=1&hist=query%2Csleeping+bag+liners.

I'm partial to a little food to get me by in airports - pack a few power bars, they're better than nothing. Also some hard candy - that's easy to spread around, especially with kids who can't tolerate flight delays nearly as well as most adults.

Also my Zune music / video player - loaded with music I like to listen to, I also load a few movies or TV shows before trips so I can watch them. Also sorta cool is Comcast's Infinity service, where you get your cable TV content over the Internet wherever you are - if I'm in an airport waiting for a flight or even at destination, its easier to fire up the laptop to watch a movie on HBO (or Netflix, don't forget that) rather than pay hotel rates for access. And I also keep my 3G/4G adapter handy, with it I can get Internet access from anywhere that Sprint has coverage. I like travel with a full laptop more than a smartphone, but you can also get most of the same stuff, just on a smaller screen.

FWIW I've never gotten into carrying spare clothing in my carryon - I tend to wear a Patagonia capilene base layer, maybe a wool sweater or shirt over that, and a fleece, or warmer jacket if I'm headed to a colder destination. The capilene is good for at least a week before it gets too smelly or troublesome - and if I need a shirt change, I don't care too much what it is, I'll pay $20-25 for a souvenir t-shirt at a news stand. Also I carry gloves and a warm fleece hat most destinations - if I leave an airport, and have to head home overland, its one less thing to worry about. Also I wear wool slacks most flights, not levis - that just comes from having to check in when you land, I'm convinced you get treated just a touch better if you dress a bit better. ymmv

I pretty much never travel without both my well-stocked computer case and a carry-on bag. Overseas is more difficult because of restrictive carry-on rules, but that's rare enough I don't worry about that except as the exception and am never happy... Generally wear a travel vest then with lots of the stuff I normally pack in the vest

On person is my Crackberry phone and normal pocket gear including a couple flashlights. Knives going in checked baggage. Almost always have checked baggage for that reason. :-(

Rolling Computer Case includes:

Computer (duh!) w/ charger
Verizon Air Card
Spare battery for Computer
Web-cam
Mouse
Phone Charger
MP3 player and Noise Canceling earbuds
Three paperback books
8.5 x 11 Ruled Notepad
Travel File
Assorted Pens
First Aid Kit with OTC Meds
JIC Prescription Meds
4-inch Scissors
Large Nail Clipper
Duct Tape
Safety Pins
2-3 Flashlights
Digital Camera
Mini-Mate Ionic Air Supply (especially useful when the guy next to you is a heavy smoker and smells like it, or hasn't taken a shower in a week)
2 x Folding N-90 Face Masks
BIC Lighter
Aseptic Packed Tuna (folding spork and paper towels all in ZipLock bag), Lara Bars and other eats
Waterless Towelettes
Back-up Funds and Credit Card (hidden)
colored zipties (to secure checked baggage)
Toiletries in 1 qt. ZipLock bag incl. hand cleaner
Travel Tooth Brush
1 Bottle Water (picked up past security)

In my carry-on:

Minimum of complete dress for next anticipated business day including shoes or boots (which varies depending on what I am supposed to be doing). Sometimes two days, just depends on how bulky it is.
2-days underwear
Personal Grooming Gear
2 packages aseptic packed Tuna and breakfast bars
Medical Kit
Sewing Kit
Duct Tape
Large Clip (holds drapes closed)
Vacuum packed T.P.
3 receptacle 6 ft. Extension Cord
Pocket Survival Pack
2 x Folding N-90 Face Masks

Outerwear, including gloves and cap/hat, I typically carry on person, may stuff an additional layer in carry-on

Sure I am forgetting something....

I can say that I have at various times ended up using virtually everything I carry.