Criteria:
a. Weather/temperature and activity at origin, airport, airplane, and destination. Layerable clothing helps.
b. Shoes that you can run in, in case of delays at security or during a connection that would require running to make your flight.
OK, normally I wear sandals ALL the time. Even in winter with snow on the ground, just add fleece sandal socks.
This is morbid, but when I fly, I dress for escaping the airplane when it crashes. I wear tennis shoes, no clothing that is too loose and that may catch on things, a pashmina to keep me warm on the plane. Once I get my bags, I pull out my Teva sandals from the outside pocket of my suitcase. 
I have never once thought about my shoes for escape! I have attractive leather/gold teva type sandles that I often wear. I either have some light weight slippers or some socks to put on when the plane becomes cold.
The bathroom floors can be so disgusting on a long flight that I have taken a flip flop with a high rubber sole to wear
in there. High enough to keep me out of the mess. I have them put them in a ziplock. No way did I want my shoes to
experience that mess.
(one of my major issue! Pee on bathroom floors? no soap? no toilet paper–disgusting).
I wasn’t going to mention “escaping the airplane” because I thought it would freak people out. But since it’s already out… an airline pilot relative tells me the same thing. Plus, he recommends leaving shoes on during takeoff and landing (the most critical phases of a flight), in case you need to evacuate. His advice to wear sensible, closed-toe shoes makes me cringe when I see passengers wearing flimsy flipflops or FMPs.
I will say it skeeves me out that people wear shoes/sandals, etc. with no socks.
PEOPLE! That is gross to walk barefoot through the security line! Bring some spare socks with you at least and then take them off!
Stretchy jeans, a long sleeve T, my warm silk scarf and long sweater. I can’t imagine flying without my socks, unless mid summer, and even then, I have foot protective, closed toe sandals. I do like to take my shoes off, but have a wide variety of sturdy rubber soled shoes and sandals to easily slip on and off, while providing some support on long airport walks.
I heard a piece in the radio not long ago about a guy who was on a plane that was hijacked. He had to go down the emergeny chute and run away across the desert carrying a woman on his back – and he was barefoot because they made them take their non-tennis type shoes off. He said he’ll never fly in any other type of shoe again. That part of the story stuck with me. Although if it had been me, I don’t know if I’d ever get on a plane again…
@BunsenBurner wrote
You better be “prepared” to evacuate on an inflatable slide.
A friend of mine had to evacuate in the middle of the night from her college dorm. When she slid down the slanted roof, her nightgown got caught, and it pulled up over her head. She wasn’t wearing anything underneath and flashed all the gaping spectators below.
Like BB, I’m wearing a maxi dress. Probably with leggings underneath because I’m pretty cold natured.
Thanks OP. 
I always enjoy the “how do you dress threads?” Since I’ve been diverted to places where I didn’t have warm enough clothing, I always pack a very heavy wool shawl (almost a cape) that can also be used as a layer over my lightweight/windbreaker raincoat. Both fold up very small. And leather gloves.
Like others I’m layering and I’m prepared for almost any temps. My travel clothes are kind of fancy but they are my regular, everyday clothes so I am very comfortable in them. My long skirts do not prohibit movement in any way. I’ve comfortably climbed fences in them.
I tend to buy a group of garments that travel well together and am getting ready to wear: lined light weight wool long-sleeved coat dress, over an embroidered cotton dress in the same dress pattern but with sleeves and hem just a little longer than the wool over-dress, over a matching embroidered cotton sleeveless dress. I will have a lightweight linen knit sweater in my carry-on along with the wool shawl. I could take off the wool dress if it got warm, but to be honest, I have rarely been warm on a plane.
Also socks with my shoes. Also comfortable emergency ready shoes. I would freeze if I wore sandals on a plane.
Frequently I wear my prescription sunglasses almost the whole time I’m in route, because it is just so very very restful to eyes, avoiding all that artificial light. I do always remove them to speak to someone in a shop in the terminal or the stewards on the plane or if I have an extremely chatty seatmate.:
eta: It’s possible my plane outfit would be all I needed the whole trip, but I pack an extra outfit just in case I spill something on myself, which unfortunately tends to happen too often.
I don’t wear socks with my sandals…so yes, I’m one who walks through the security line in bare feet. Oh well.
What do you do with the socks you have on? Tak them off and put them in a sealed bag until you can wash them? You know…the bottom of socks get dirty when you walk on the floor too.
I’m not germophobic at all…and I can’t fuss about this.
I look fabulous when I travel…to me…and that is all that matters to me!
Yes, I have a small ziplock in the side pocket of my carryon for the “TSA socks.” They get washed after the security. Foot fungus is easier catches than cured, so I do not take any chances. And no socks with sandals for me!
I remember in one European country pax who were going through security at the international terminal were given disposable footies. And I got yelled at for putting my shoes into a blue bin - apparenly, shoes only were allowed in brown bins. Makes sense!
Like alh, I often wear cropped leggings under my maxi dress. And I would never ever travel commando. So my fellow pax can breathe a sigh of relief that no one will get flashed.
Since I usually also wear a silk tee under the sleeveless dress, in the event of the zombie apocalypse (like on flight 462) I could take off all my outer layers so all I had were tee shirt, leggings, sensible shoes. I think I would still need to keep my wool shawl for warmth after we crashed. And probably my raincoat.
eta: I make sure my dresses are just above my ankles, so I don’t trip on them going up or down stairs. I can probably wear them in an emergency just fine. If need be, I could tie them around my waist to get them shorter, like women did their petticoats in earlier times. Sometimes I do that while gardening if it’s really wet out.
If it is an international flight I wear shoes that are really roomy and comfy. I learned a lesson when I went to New Zealand–a 20+ hour flight from the east coast of the US. I took my shoes off (always wear socks) and by the end of the flight I could barely get them back on. I smashed down the backs as I walked through customs because my feet had swelled. Other than paying attention to shoes, I wear whatever–usually something in black.
Bromfield’s post reminded me about another important point - my ankle-long dress covers the compression knee-high socks I wear on those 5+ hr flights. They certainly help with leg swelling, but I am not sure they would be effective on a 20+ hr flight!
I just got a pair of crops at Lululemon that would work great as travel leggings! They are called Align crops… Not cheap, but the upside is that their softness makes them feel like a second skin. Add a long top, a scarf, and a pair of Keds-like sneakers or flats, and it is a cute travel outfit. I like these Kate Spade cuties:
http://www.keds.com/en/keds-x-kate-spade-new-york-triple-bird/044213961499.html
Cute!^ Thanks for the reminder I bought a pair of watermelon pink Keds a few weeks ago and haven’t worn them yet -
Yup it’s pretty common. But more likely is that they’re just flying home after a meeting where they may have stayed overnight.
My last couple trips have been day-trips, out at 8am return flight at 8pm. It makes for a long day but it’s nice not having to schlep luggage. I’m never in a suit though, thank god. Cab drivers sometimes will sometimes ask where my luggage is on those trips :))
Avoid clothing with reflective decorations, even metallic coated plastic deco.
I have couple of dark-color tops I like but they have tiny metal-color beads, crystals, etc, on the chest area.
They got flagged at the screen, but both times TSA just looked at me (on the chest/breast) 
and let me go without pat down. 
Even plastic hair clips (with crystals) show up. It’s ridiculous. Hair pat down
http://www.amazon.com/Crystal-Rhinestone-Assorted-Accessories-Colored/dp/B01452Y1BC/ref=cts_ap_1_fbt
I just take all jewerly/plastics off and put them in zippered side pocket on my purse before the x-ray/microwave.
My NYDJ jeans with sparkles/mini-crystals on back pockets caused uncomfortable pat down. :-&
I ended up flying from very chilly D.C. wearing jeans and a 3/4 sleeve length blouse, socks and clog style shoes. I removed the socks pretty quickly after arriving in South Florida! It worked out fine. We lucked out with the weather down there, it was perfect temps, low humidity, actually pretty chilly at night. I was really surprised as I was expecting 90 degrees heat and humidity.
I travel very frequently for work (2 - 3 weeks out of every month). We have Mondays and Fridays set aside exclusively for travel, and I work with the clients Tues - Thurs. For travel I dress exclusively for comfort. I’m not particularly fashionable anyway, but I wear comfortable pants, socks with walking shoes, a jersey knit top, and depending on the season, a coat/jacket/sweater. Since I have TSA Pre-check I don’t have to take off my shoes.
I always have layers - often I’m freezing on planes, and sometimes at the client sites it’s really cold or really hot. The coldest I’ve been is in Alabama in early September, where it was in the high 80s outside but the room was in the low 50s. One of the clients wore a winter coat, fingerless gloves, and brought a blanket for her lap!
I always pack assuming I may accidentally spill my breakfast on myself and need to change clothes - so I have extras of just about everything.