I haven't been to LAS in the summer, but I have been to MCO, which is pretty bad

I wear my usual flying attire - a pair of jeans and a top. I always have some sort of sweater/hoodie with me. How cold it's at home when I leave dictates the sweater or hoodie I bring. Sometimes it's polartec

I usually wear some sort of shoe or clog and have very thin merino wool socks I wear with them. If I decide to wear sandals I always have socks.

When I arrive I just take off the sweater. While it's miserably hot and humid, I'm really not outdoors all that long.

I'm going in a few weeks and am substituting a thin pashmina wrap instead of a light weight hoodie. It was suggested by someone on this board that it's actually warmer/better than a hoodie alone, and it folds up to next to nothing.

I'll report back if I freeze or not