I try not to look like a slob, but I also go for comfort, and ease of going through security. This spring we went on a trip with a 13 hour flight and I wore stretch cotton slacks, short sleeve tee, cashmere cardigan, large soft scarf, and a Patagonia nano puff jacket. We left our house in freezing temps, and arrived at our destination in warm temps. I only took three pairs of shoes, so wore the bulkiest which also allowed for warm socks, and have a quick lace system which makes them easy to do and undo. I tend to freeze on planes. The jacket stuffs into a pocket and makes a nice layer if needed. I can even fit it in my purse.

I'm on team knit dress, leggings and cardigan with one important addition; a shawl/scarf that I can use as a blanket if necessary. I run cold and sometimes find planes freezing.

Knit dress and leggings are a great go to. If you want to wear pants try ponte pants and an oversized sweater.

I like to wear loose thin jeans with lots of pockets, a nice and soft organic cotton top and a zippered sweater with pockets. Lots of pockets are a big help for me when I travel.
I also carry a small sheet and a soft light-weight blanket. I line my seat with the sheet so that the seat does not stick to me and make me sweaty, and I cover myself with my blanket and I am ready for a nice cozy sleep.
I also take a pair of cozy Birkenstocks to change into.

I aim for polished comfort and layers when traveling on the red-eye or for long flights. I've tried the jersey dress and leggings combo but don't find that as
comfortable as a pair of slim, stretchy pants and a knit top; on me,
dresses get twisted around too much when I'm squirming to get
comfortable after sitting for hours, so horses for courses. I also usually travel with a nice looking jacket/topper/trench to throw on when I get to my destination to cover wrinkles and any spills.

I'm a big believer in wearing "sprinting through the airport" shoes
that are easy to get on and off when going through security. If I'm
wearing boots, I change into those little Dr. Scholl's foldable flats
before going through security and carry my boots in my hand.

I also carry a large Le Pilage tote inside my cross-body bag which I unfold and use to corral all my stuff before going through security. Everything goes into that tote--my crossbody bag, iPad, water bottle, magazines, meds, snacks, even my jacket (if I don't put it into the outside pocket of my carryon)--everything! That way I just have the Le Pilage and my carry-on bag to worry about when I'm getting on and off planes and making connections. I get through security faster, board easily, and never forget anything if I'm in a hurry or get distracted at the last minute. The Le Pilage stays at my feet during the flight and only the carry-on goes into the overhead compartment.

After travelling with my sister who regularly gets bumped up to business class, I've also learned to bring along a pair of fleece socks when I'm in cattle class for a long flight. I take off my shoes and wear the fleece socks over my regular socks for the duration, even when walking around the plane and going to the washroom. Business class gets similar socks handed out to them (lucky sods!). The socks get sealed into a baggy (I don't like to think of what is clinging to them ) until the return flight, or until I can wash them.

But I'm blown away by the thought of trying to change in an airplane bathroom. Those floors get pretty nasty after 8 hours, so I'm thinking you'd have to be a contortionist to keep your clothes off of them. (See above comment about yucky socks!)

I like to be comfortable but I am always cold on the plane so I wear a wooly cardigan and yoga pants. I always take a shawl to wrap up. Slippers socks are aways good.

I always wear comfortable jeans, a blouse, blazer and a trench coat with ballet flats. I have been bumped up to First Class many times, so I keep this in mind when dressing. I'd like to find a really pretty cashmere pashmina as well, that doesn't look too wintery. I get cold on airplanes even in the summer.

Just came across this:
http://youlookfab.com/welookfa.....light-wear

Ponte knit dark colored pants, compression knee socks from Nordstroms, slip on athletic flats,. On top I layer ...tank over wireless bra, dressiest dark knit top I have at the moment, knit jacket, big scarf, coat.

I just returned from a trip to visit family. I wanted to look stylish en route, but I ended up wearing my most flattering, good quality black yoga pants, a black tank top, and my cute new gray sweatshirt with a tiger face on it from Forever 21. For shoes, I went with my cozy black, gray, and fuchsia plaid Toms. I was very comfortable, and felt reasonably put together. I was going to wear my ponte jeggings, but they actually sag and droop after wearing for a long time, and the flight was 4.5 hours. Next trip, I may try wearing a jersey dress, cardigan, and slip-on shoes.

I'm an outlier, but I wear comfortable jeans on the plane. My last few trips have all been in cold weather, and my uniform has been skinny jeans, knee high boots (which are actually quite easy to get on and off for security), striped pullover, maybe another layer underneath like a turtleneck, scarf, ponte knit moto jacket, and my winter coat. I bring soft slippers to wear on the plane. One of the benefits of this ensemble is that I am wearing some of my heaviest items so they don't have to go in my suitcase and count against my weight allowance.

I'm a tunic/dress and leggings dresser for overnight flights, with a shelf bra cami underneath (real bra comes off when I brush my teeth, sometimes right before boarding, sometimes after meal on flight depending on my schedule). A petite ponte knit dress with sleeves and pockets along with Danskin supplex leggings (pretty high waisted) are my current go-tos.

For shorter day trips (U.S. transcon or less), I'll do jeans/trousers with a shirt and jacket. Always a pashmina, even in the summer.

I strongly recommend wearing flat shoes or boots on the plane. In case of emergency, you do not want to be wearing heels.

I'm adding another vote for dress/tunic plus leggings for longer flights. Flats in the summer or a pair of slip on boots (I have a pair of motos) to save packing space and get through security easily. Add a cozy cardi or scarf for extra warmth as needed.

For travels under 6 hours or so, I'm usually willing to wear jeans, but I have mostly straight legs, not skinnies, so they are still pretty comfortable. In this case, neutral tee plus colored topper of some sort to pull it together.

I've travelled enough over the past year or so that I get bumped up to business/first class every couple of flights, and I do feel a bit underdressed compard to the (mostly) older men in business suits crowd. Not enough to give up my leggings, though!

My coat either get carried or packed, depending on suitcase space. This often means packed on the way out but carried on the way home, so I have room in my suitcase for other purchases.

I am actually also a jeans-on-planes person, but I wear my most comfortable jeans and sometimes unbutton them. And usually a tshirt and cardigan. I usually wear makeup so I look a little more refined. My converse are the best shoe choice if I have to walk through airports during a layover, but I often end up wearing my combat boots instead to save room in my suitcase.

My main concern is not comfort but sweatiness. I don't regulate my temperature well, so I need to make sure I have a few different layers. And if I'm going straight to a social event after flying (I usually schedule things really tightly), I make sure I have a clean top to change into and I wear jeans that don't pick up odors.

Have any of you noticed the huge range in how long you can wear different denim without it smelling worn? I have some jeans that can go for days and others that pick up a scent (not awful, but noticeable) after a few hours. I used to think it was just fabric content because all-cotton jeans tend to go longer, but my R13 jeans are something like 20% polyester (usually a big no-no for me) but I can wear them for days on end. Which is good, because I do wear them all the darn time.

Greyscale, I think it must be something about the dyes. I have some jeans that seem to be very smelly after a short time, which drives me nuts.

Anyway, I'm another jeans-wearer. Since I wear them to sit at the computer all day I'm used to them. I always wear several layers, even in summer (camisole, top, cardigan or jacket) and carry a pashmina and slipper socks. Shoes are usually something that I can slip off fairly easily unless I'm on my way to do fieldwork and then it's my hiking boots.

In the past few years I've tried to pack lighter, so I do my best to only bring a tote bag or medium sized backpack as a carry-on. Usually when I fly it's trans-Atlantic and I know I'll be checking a suitcase (I like to bring a few bottles of British ale home to the US and vice versa) so my carry-on only has things that I will want on the flight, valuables, and an emergency change of clothes.

However, if I'm going on a road trip with my parents I usually wear yoga pants or similar. I might switch to some sort of knit pants if I find some I like -- I'm not averse to wearing yoga pants in public.

If I traveled a lot for work I would go to J Jill and invest in their whole Wearever line (or something very similar - I think Eddie Bauer has a similar line) of mix and match knits in that rayon knit that is dressy.

For road trips, it depends on whether I will be in and out of the car a lot or not. If not, I think maxi skirts/dresses are really nice, because they're comfy, cover you up if you want to sprawl, and feel more pulled together than sweats. If there will be a lot of stops, I tend to go for jeans, preferably one of my looser pairs, so I can have everything in my pockets and not mess with a purse.

Here are snaps of the feature I mentioned in the December InStyle (sorry about the glare, it's hard to photograph glossy paper with a phone):