It does help. Don't let these people tell you otherwise.
Shoot an arrow with the vanes not aligned, then shoot the same arrow with the vanes aligned... you will hit two different places.
I was off 2 inches to the right when I moved from field points to broadheads, then aligned the vanes, and I am now shooting the same with broadheads and field points. Had I not aligned them, I would had ended up like most people having to re-align your bow because of the broadheads....That's an old wives tale!

If alighning your broadheads and vanes makes any difference then your bow is out of tune. If your bow is tuned properly then alighnment of broadheads and vanes is not neccessary.

An arrow does not fly straight on take off, it oscillates and spins. The fletchings job is to dampen this oscillation. I don't see how lining your blades with your fletching will do anything.

no difference
Jeff
"Stop Hacking, get out of the woods"

I didn't expect to open up a controversy but I have enjoyed the responses and regardless of whether it helps or not, thanks to all that took the time to reply.

I'm not going to get into the debate of whether it helps or not. But, if you ever hunt from a pop-up type blind with the shoot-thru windows the blades and the fletching need to be aligned for better arrow flight thru the windows. Just a tip.

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Hunting the Piney Woods of Deep East Texas.

That's about the only place where I could see that it would make any difference at all since the arrow doesn't begin to spin until a few yards out. If you think about it the vanes would really need to be slightly offset from your blades for them to be traveling through the same plane of air. That would also depend on if you had straight vanes, offset vanes or helical and how much offset or helical you have because your arrow would spin faster or slower depending on your vanes.