I am sure you have grooming standards laid down at your airline which were there when you joined. I expect it says something along the lines of hair will be neat, tidy and blah blah whatever else. It may be in your culture that dreadlocks are accepted as a normal style of hair but you work for a UK airline where they are considered by many to be scruffy. I don't think you have a leg to stand on, oh actually you are in the UK aren't you, you could probably win a court case as the UK is so overly politically correct that if you even utter discrimination or racial oppression you will win, unless you are white and British of course
