Well, if you ever run in to me while traveling (and I hope you do), I'm always dressed in Nike. From the shoes (no metal) to the pants, tops and jumper or top. It's usually a track suit because with the new Dri-Fit stuff (fabric that breathes), it's absolutely wonderful on long hauls and i can easily rinse and wash to dry over the hotel room vent for the trip back. I doubt if I've worn anything but this for the past 18 years traveling. If I've got biz on the other end, I slip into the stalls and quick change myself into the zoot suit, same with arriving at the airport after some biz. I don't think i've ever fown in a suit.
Of course the question i usually get from someone picking me up or meeting me is have i just come in from taking a run or from excercising. I have found sportwear to be the most comfortable. It's always black or blue so that the dings and spills aren't noticeable, especially when i've been attached by a child sitting in front or behind.