You could look at the problem from another angle too; what not to wear!The last thing you want is for the board to think "what kind of schmuck is this" or "look what the cat dragged in".
I don`t think that you`ll get a job based entirely upon what you wear, but looking sharp is never a disadvantage.It`s a way of giving the board the message that, yes, you understand that they are important people and show them their due respect.A haircut does wonders, and for shiny shoes... if you can shine them, then you`d better have a spitshine
That said, make a good first impression.Give a nice and firm handshake (nobody likes the receive a weak handshake - it gives the impression that you could care less).Take part in the interview as well, don`t just sit there and answer the questions. Remember you`re a pilot and therefore should be able to take some initiative.Be on time!Preferrably a bit early.
And last but not least, shower, scrub and shave.Cleanly boys don`t misbehave! (Stole that from NOFX)
Lotsa luck!