On the backpack note, i still don't think it looks professional, no matter who is toting it around. As for stickers, it's almost of the same accord, if you do them tastefully, only have one or two, it might work. But when the bag is covered in stickers, going every which direction, just for the sake of fitting another one on, it detracts a little bit, at least for me.

Thus far, some of the most "professional" looking crews i've seen are normally from foreign airlines. Have watched the Indians and Germans split crowds in Dulles as they walk through the B terminal. Jackets Buttoned, Hats hunkered down, brass gleaming, and a pyramid of identical looking flight attendants all following in formation.... awesome sight.