The local airport which I fly from here in Briatin is currently recruiting ATCO's. I don't think you'd have a problem with wearing a kilt on duty as a civilian ATCO in Britain. Most civilian control towers and radar stations which I have visited whether privately run or government run, the staff have been dressed casually. The only place there is a strict dress code is on military ATC stations where staff are always in uniform. It sounds like the US government runs their ATC as a military style operation; while this does sound unduly restrictive of staff rights to dress comfortably, it is perhaps an understandable attitude in light of terrorist threats to civil aviation. By the way, welcome to the forum.