In my opinion I don't think I'd be a newhire at Delta without the job fairs I attended.
Number one you get to get ask specific questions on how to better your resume' and which career moves to make. Often times what the airlines are looking for are different from what you've heard or what you think they want.
Number two you get a chance to put a face to the name on your application. Remember though if this can be a good or bad thing so be prepared and have a positive attitude when you show up.