Plane travel is 100% different than car travel.
One needs to dress for plane travel. Sure, comfort is important, but one does not want to schlep through the airport looking like a college student after an allnighter. So what to wear? Dos and don'ts:
Do wear a wrinkle-free dress, like a knit wrap dress or a sheath. It's comfy (no waistband), and it'll get you more respect (and sometimes a better seat.
Don't wear hose. Ever. Circulation is good, and waistbands are bad.
Do wear shoes you can walk 100 miles in. Flats or heels (boots are comfy, but a pain in the rear end to take on and off for the security dealio), your choice, but make them pretty.
Don't wear baresly too short slacks, same tone trouser socks, and pseudo-heel loafers. It does not work. Trust me.
Do drag a bag on wheels, whether for work or for play. I love the old-skool satchels, too - even today drooled over one at baggage claim, but really, they're just not practical to be schlepping around. Way too heavy for those of us without drivers or bodyguards.
Don't forget the makeup. Minimal, yes, and moisturizing, yes, but please wear some. Carry on a little touch-up bag, if you have to.
Do carry a savvy purse. Big enough to carry a bottle of water, but pretty enough to get compliments.
Do wear sunglasses. The whole time. Aviators, which aren't too dark, and are so Rock Star, or Jackie-O-esque glam. If you never take them off, they'll wonder who you are.
And always, always, always, keep a Mona Lisa smile on your face. Even when they bump you to the next flight (which they won't 'cause you're a Rock Star) or Freshens is out of double-dutch chocolate.