I don't know about "major airlines"
However, NJS's Dash 8 operation in northern Australia used to wear RM Williams beige moleskins with a ochre coloured shirt. Akubras were the hat of choice. I thought they looked great and much better than the blue and whites.
The uniform of the Child flight (I think??) helo pilots consisted of blue trousers and a denim shirt with "Child flight" embroidered on them. Again, smart and suited the operation.
Unfortunately, I can't see many airlines going away from the traditional look. Some don't have hats though. The public just like to be "reassured" I think.