Also, consider Tencel. Many different clothing makers use it, so shop around, but I can personally attest to its ability to arrive after a long flight and still look and feel good and not even have an obnoxious smell. I've flown from northwest Florida to far-flung points such as Juneau and Dublin in Tencel, and though I was worn out after each trip, my clothes held up great.

I've also found that even if you don't generally like drawstring waistbands, they're great for travel--very comfy and less fiddling in restrooms.