Usually Jeans, RAF Aircrew socks, cotton vest & pants, RAF Aircrew T-Shirt (long sleeves and Turtleneck), Old SAS windproof (cotton), desert boots or Timberland boots and RAF Issue cape leather gloves, and a cap plus sunglasses.
In the winter maybe one more cotton layer, and cotton long johns, plus silk inners for the gloves.
Comfortable and hopefully safe ('ish).
I also think that Richard Hillary comment in 'The Last Enemy' about gloves is very true - one of the aeroplanes I fly has a header tank just in front of me - not even a firewall between me and it............. (Cub J3) - I often think of Geoffrey Page when I see it. I'm also mindful of lessons learned around 'Anti-Flash' learned in the Falklands. I stay well away from Nylon as it has bad static properties and melts like.............a melty thing !!
http://en.wikipedia.org/wiki/Geoffrey_Page
I never fly in shorts or short sleeves, or flip flops (which I have seen).
Arc