I am traveling on Dec 2nd, to Peru: for 10 days with one back pack, but also bringing a fold-up duffel, for there and the travel home, and buy some basis tees, a skirt, a hat, whilst there,) As having been advised from some other travel-sites, I will review each item on the check-list, then, take a moment each for each item. My plan is to travel light, so I am studying how that can be. I am starting by seeing myself in very comfortable, somewhat of the moment

So, I am asking, what should I be wearing on this 10 hour travel from NYC to Peru, in order to stay comfortable?

How exciting! I would wear layers that are either loose and non-restricting, or in stretchy/knit materials. I'm not sure what the weather will be like in Peru -- are you bringing a winter coat? If you won't need it in Peru, consider leaving it behind. You'll only have to suffer between home and the airport in NYC, and that way you won't have to lug it around on your travels and have it take up space. (That's what I did when travelling from Toronto to southeast Asia in January a few years ago.) But don't dress too lightly for the plane -- you'll want a cozy sweater/cardigan/fleecie as it may be cold, but layer a t-shirt or something underneath in case it's NOT cold! And comfy shoes, of course. As for non-clothing items...if you think you'll want to nap, bring an inflatable neck pillow and an eye mask (can be bought at the airport). I always bring extra water (buy after security, or fill up your water bottle once you get through). Have fun!

I have read to wear compression socks on a long flight. Tissues, lip balm, hand sanitizer. I like slip-on shoes so I can give my feet a break.

Not much to add, just that jeans aren't comfortable on long journeys. But you hadn't mentioned jeans anyway. :) I hope you have a wonderful time.