I'm not sure that the distinction is valid any more.
My main profession is Engineering; I'm often found in a suit (white collar), occasionally in overalls (blue collar, actually mine are green), when I've no meetings, jeans and an open necked shirt.
On occasion I fly aeroplanes, where the clothing depends upon aircraft and role.
However, these two jobs have something very much in common. They are critical, skilled, highly trained, professional jobs. So, I'd count both Engineering and flying as "professional", and the white.v.blue collar is meaningless.
Scientists, doctors, archeologists... there are many other professions which share these characteristics. The blue.v.white frankly belongs in the unionised 1960s and 1970s and should be left long behind.
G