I've always thought of him as basically a James Garner size/shape, maybe an inch or two taller, but with medium brown hair that's a tad tough to control...with 5 o'clock shadow by mid-afternoon, but no beard/mustache. Not huge, but big. Very centered, balanced, surprisingly light on his feet, and of course master pilot fast. His personality and self-confidence are what observant folk really notice, not his body, per se, other than general perception that he's a pretty big guy (definitely not wiry, but also not fat).

There's a reason you haven't HAD to write physical description before: it hasn't mattered, at least not compared to the personality that lights up and animates that largish rugged body.