I've got 99 fletching, and trust me it doesn't help you make much money. It's easy to get 99 fletching, but just like cooking, it really doesn't make much money.
Fletching isn't easy no more, since its now messed up thanks to the GE, yew longs, and mage longs don't sell very well in GE now and tons of people are selling them on fourms, yanille, so you have a hard chance selling your stock unless you got like 50mil and can wait to sell all at the end and it doesn't make good money.
I don't know I have 99 fletch and I make quite a few mils a day. But I make my own things. Such as rune arrows. I make my runite tips and I kill my own chickens. So ya I make quite alot of cash.
Fletching is good money and very fast now bcause of the GE IF you know what to fletch. Can't tell though, because it's kinda on the dl at the moment and I'm makeing 200k and hour plus 300k xp if I go really hard for an hour straight. (rare that I don't break)