The only time my uniform didn't include a tie was when I was working in the Caribbean. White short-sleeved shirt, black (long) trousers and black shoes. No jacket (thank God) and no hat either.
Otherwise, I'm happy to wear whatever the company decides is uniform. They provide it, they pay me to wear it, and I'll wear it with pride, and try my best to keep it looking good.
It helps passengers' confidence if the drivers (when they see them) look the part - look professional, not like escapees from a low-budget barnstorming movie.