Comfort and style is a balancing act when you're lugging a 20lb carry-on. Resist the urge to throw on your sweatpants with the worn bottoms; slip into something else. You can do it.
My go-to airplane to daytime outfit is a simple formula. A matching top and bottom with a zip jacket looks put together and effortless (because it is.) When flying somewhere on the colder side, I opt for layering an oversized lightweight coat for comfort. Sleek look coming on and off the plane. I was essentially wearing silky pajamas. You'll feel and look better in real clothes, even if you're stumbling off an 8 hour flight.