Think "conservative" for the interview, and no, I am not talking about William Hague (bleurgh).
As suggested, a smart suit, not too much make up or jewellery. Its best to look like a line pilot when you are up in front of the interview board, that way they can picture you as an actual FO.
However, don't be afraid to come across as feminine but know where to draw the line - I am sure there have been previous occurrences of female interviewees trying a little too hard to play on their male interviewer's weaknesses. Be professional.